Too late to act like a child

Why was I so mature then other kids my age?

Why were they so immature?

Why can't they act their age?

They do act their age.

They act like children because that's what they are.

I just matured too fast to realized this.

I don't act like a child even when I am one, and now I feel like once I want to start acting like one, it's going to be too late.