Is it normal to be a kid again mentally?

This isn't really that serious a thread, I'm just seeing of others feel the same way.

I was a stroppy, moody, sour-faced teenager who barely even used the words play or fun. I was super serious, easily agitated, flinched a lot and cried a lot too. I listened to bad metal music and didn't have many friends. I was immature in a way but not in the way I'm going to talk about here.

After that when I reached adulthood I sort of went through a period of recovery and now, sometimes I feel like I'm back to being a little kid again. I like to play, I like to pretend, I like to run around for the sake of running around. I like to pick up insects or spiders and hold them. I like to climb trees. I like to get the window seat. I stare at everyday things around me as if I'd never seen them before and get the same kind of awe out of it. I play with my kid siblings as if I were their age. I like to tell it how I see it. I like to basically do things I used to find fun when I was about 6 or 7.

I seem to have gone backwards with some things too, though. Like I don't understand certain things adults should understand and I'm not really all that sure if I ever did understand them at some point and just forgot or if I never learned them in the first place. Things like picking up people's subtle cues or saying things that seem innocent to me but actually mean something different. It's hard to explain actually because I have a hard time understanding these things. It can be a hindrance but I feel when I'm being open and honest as possible I can't fault myself. Just learn and move on.

Overall I feel a lot happier than I did 10 years ago, a lot more carefree. I still feel like an adult (and have adult relationships) but like a small part of me has recessed back to childhood and is learning certain things from scratch all over again (in a good way) from a new, fresh perspective. Anyone else feel this way?