I have some questions on Fallout

They're both good, IMO. Fallout 3 follows a more traditional good-vs-bad play style and seems like a more coherent world. New Vegas is more choose-your-own-morality style and is less coherent, and as a result feels slightly more free and silly. Both games are very easy to get into, depending on your difficulty settings. The few stats there are aren't overly complex, and the perk system describes each perk as you pick it.

It's definitely an RPG, so it may take some time to get used to, but it's not a complicated one. You should pick up on it relatively quickly.

FO3 is done by Bethesda, and FNV is done by Obsidian. If you know these two developers well, you will know what they are good at, and what they are not. Bethesda is a master of creating detailed open world, while Obsidian has much better writing and story telling. Both games are a bit glitchy. Since FNV was built on the success of FO3, it is quite safe to say FNV is better. And old FO fans usually prefer FNV. I'll say both worth trying.

sigh them bugs...