I can't wait till I grow up是什么意思?

I can't wait till I grow up是什么意思?
A: Have you done your homework?
B: Not yet.
A: Then why are you watching TV?
B: This is my favorite show.
A: Go do your homework.
B: But, mom!
A: You can watch TV after you do your homework.
B: But the show will be over.
A: There will be another show next week.
B: Please?
A: You know the rules.
B: I hate the rules! I can't wait till I grow up.