Where should I volunteer at?

McDonalds

As I know that autistic children often bring their parents to the edge of collapse, I would suggest stay with them.
Edit: I have a great deal of respect for people who volunteer!

I think you should continue to help the children, because you already have the experience. And I'm not sure how easily those children might be able to warm up to a new person.
It is easier to find a new person to volunteer at an animal shelter, than to find someone to help autistic children.

It's offensive that you put people and animals in one basket :/

Help the animals, it is we that are the pariah of this planet. and I mean all of us. not any particular group,race, just humans. I don't mean to be offensive. its just my view. Have a wonderful day! ta da!

The animals, because their lives depend on it. Help them to find loving homes and avoid being killed just because they're old or unwanted. You can make a difference for many animals and the people that adopt them too.

Stay by the autistc children, because you have experience with them and i know how hard this can get for the parents.