How old do u have to be to sit in the theater by yourself

I would say 13 and up.

Depends on movie rating. If it's rated G or R. It's better to have someone with you. You're never safe by just the looks of a place Lots of creepy people , you'll never know who is good or bad.

Depends on the movie rating. As long as you are mature enough to not make a fool of yourself you can sit alone as long as it isnt R