I'm not sure where else to post this.

Easier way to lose weight ? ... Reducing the meal portions little by little, u can eat the same stuff but reducing portions lil by lil :) That will help a lot , also drinking water and trading snacks for "healtier snacks" like pineapples with sugar or stuff like that, that will help you a lot to reduce weight, later u can go for sports. U can drink sodas but try to do it once weekly , mostly drink a lot of water, cold water if that helps you to feel better, even some Nestea sometimes so u dont get super bored of water.

One other thing to bear in mind with the sodas, if you've been heavy on them and they are caffeinated you're going to have a caffeine withdrawal. That can come with some pretty big headaches, so you may need to supplement the caffeine (coffee, some teas, caffeine packs) to come off it slower, just don't sugar up the coffee.
If they were non caffeinated sodas it should go way easier.

I noticed you kept asking "how much should I eat a day?" You can compare to how much other family members and friends are eating.
If they are eating a lot less than you, maybe you are eating too much. It does depend on several things like body type and natural energy their bodies use, but you can get an idea. Don't ever aim for an almost empty plate, though.

For me the Atkins diet worked great. Hi protein diet with very few carbs.

One great thing you've got going for you is your age. Its super easy to lose weight in your teen years. You always hear adults talking about how hard it is to lose weight. It will not be for you. You just have to really want to do it, which it sounds like you do.

I've seen a lot of worthy comments in this thread already.
Something to add:
You don't really need to learn in detail how "calories and stuff" work. My experience with this was using the myfitnesspal app - the thing allows to calculate your requirements and monitor the stuff you eat in a fairly easy way. And it's not only "calories", but monitors the balance in carbs/fats/proteins (and other stuff too, but the information about those is often missing for many foods).

Also try stuff in moderation, going "all in" is very likely to get you down and abandon the stuff you undertake before any relevant result (and possible, add some damage to yourself). And if you really are up for this, don't forget to take a "before" picture, so you can see (and share!) the result afterwards (yet, remember, it's going to be "months" or longer before the results start to show, although at your age oh, yes, I'm so old it might be a lot faster, which is a great plus).

Good luck.

Keeping a food journal and just being aware of what you're eating has helped me a bit. It's not as good a solution as exercise (I lost a bunch of weight when I started walking an hour a day, and gradually put it back on when I stopped exercising at all) but it can help with the basics of understanding how much you're taking in; you can find an online calorie calculator to suggest your intake, so you can compare what you're eating with a target consumption and hopefully lose some weight there. Also, substituting water for sodas, even diet sodas, or only having certain foods (chocolate, soda, etc.) once a week or as a treat for special things can help significantly also!

I must say, I'm surprised that there were no trolls on here acting the fool. Well done Internet. :) Good to see a caring community.
My two cents...
...although it's not always easy, cut out processed sugar. you can still eat good food without needing to watch calories that way. You may not require extreme levels of exercise, but it's still a good addition. Trouble is that people go through withdrawal and deprived sleep in the first few weeks of removing processed sugar from their diet, which makes it super had. But the rewards are easy afterwards. Maybe for starters you could just reduce the amounts and not go cold-turkey and go through withdrawals like coming off drugs.

Eat in deficit,
Small Fasted Walking sessions,
Drink Water,
Cut Sugar and Salt

The heavier you are, the higher the Calorie Maintenance, it is recommended to eat 500 less calories than your Calorie maintenance, I would recommend seeing a doctor for advice and also to get information on Weight, Height and Body Fat %

So much good advice in this thread. Thanks guys!
I'll add a few things I've noticed too:

1) When eating a meal, don't eat til you're "full" (i.e. the point where you couldn't possibly eat any more). Eat slowly and only til you're not hungry. Your body and brain need to have enough time to recognise when they are satisfied. If you're worried you haven't eaten enough, you can always save the remaining food for later when you are hungry again.
2) Losing weight is not about starving yourself. Yes you will sometimes feel hunger but this is a good thing. You're learning about the signals your body gives you. When you first start to diet you might think you're hungry almost all the time, but as time goes on you'll find your body starts to realise it can get by on a bit less food. The idea is that you still should eat when you're hungry, just not as much as you used to.
3) Avoid overly processed foods, especially ones that are somewhat high in sugar. Often a lot of supposedly healthy food in the supermarket (e.g. light yoghurt) tries to trick you into thinking it's healthy with claims like "99% fat free". What they neglect to tell you is that to make the yoghurt taste good it's loaded with sugar instead and it's probably worse for your health than before that substitution was made.
4) Losing weight takes a holistic approach. It really does take a lifestyle change. You don't have to be running marathons, but being at least moderately active (getting your heart rate up or getting a bit of a sweat) at least a couple times a week will make your weight loss easier (less hunger). Don't overdo it though. As others have said, if you harm yourself it's going to be hard to exercise how you want. Swimming is great exercise for this reason as it's good for your joints. Running on the other hand, especially if you're currently pretty overweight, could be hard to do without some discomfort or injury.
5) Be willing to LEARN about health, nutrition, exercise and so on. You will need to learn about foods and things like nutritional content and their energy. For example, coloured vegetables are the best, like red, green, orange. Potatoes don't count as vegetables.
6) Sodas (or "soft drinks" as we call them here) are a bad idea. They are an occasional thing only (e.g. one can a week or less on average). If you must have a soda, aim for the sugar-free varieties. Yes they have artificial sweeteners and some people are really paranoid about those being linked with cancer but the evidence is very very thin on that matter. The point is not to consume to excess. Fruit juice is not healthy to drink either. Even if it has nothing added, it's still way too high in energy and almost certainly not helpful if you're trying to lose weight. Water is the thing you should drink when thirsty. If you don't like the taste of water, try drinking it colder

Essentially it all boils down to:
Eat real food
Not too much
Mostly plants
Exercise more (than you were)

This is a slight modification to Michael Pollan's advice of "Eat food, not too much, mostly plants" from his book
In Defense of Food: An Eater's Manifesto. To be honest I haven't read it but I've heard it has good sensible suggestions.

Just to add a few thoughts to the many replies:

• Ask your doc for some support, as they can check out any health issues, and may be able to help you with medical stuff that's getting in the way of exercise etc. As well as making sure your asthma and other conditions are under control, they may be able to point you to local resources to help you with nutrition, exercise, etc.

• Focus on doing good stuff for your body: Learn to cook more of the foods you like, and chuck in plenty of veg. Make a food diary if it helps. Gently increase exercise (within whatever healthy limits are for you) and enjoy the process of building up strength and fitness gradually. If you find it helpful, track your progress in terms of distances walked, portions of veg eaten, etc. Give yourself credit for the gains you make.

• Find someone to share your goals if you can. That could be a local group, a friend who wants to go walking, cycling, or swimming together, or even something online. A bit of company or mutual support goes a long way.