I know what you mean. I'm unsure if it has to do with asd, but i, too, have it, and also do simliar things as you mention. especially the feeling as more than one person... I've often wondered about a DID diagnosis on that. but its not something i plan to ever bring up to others IRL. and the more i get older... the more i wonder...
but yes, you're not the only one who experiences these kind of things. Sometimes we just have to let the inner child out, and be free, and not caring what others think(easier said than done) ; just have fun- there's no rule that says people aren't allowed to have fun.. and i find that most of those who point out others and call them "immature" are usually the true immature people.. as the one being called "immature" are able to be the mature one in the situation, and take it in, along with examining the truth to it. (i would think a true immature person would likely come right back at the person and it would be a big drama fest). I may be very wrong there. but it's just my opinion.