The last thing I should do as a kid.

[Flailing Escapist]

Get hammered. Its the best way to enter adulthood

 

[Rule Britannia]

1. shit your pants...

2. Go to your mother with a splinter and say "I got a boo boo"

3. sneak into an R rated movie (I'm not sure what age that is since i live England)

 

[Squilookle]

Well, if you're doing it right, the last thing you should do before you become an adult is...

...get to third base.