My mother is putting me on birth control soon. apparently, if someone comes in you, the depo shot is sure to not make you pregnant. is this true?

Contraception: Oral contraception and depot shots are very safe and effective methods of contraception. Efficacy rates vary but are usually 95-99% percent which means they will work the majority of the time! There is still a small chance of becoming pregnant with even without a complete ejaculation. Your best bet is to also have your partner wear a condom.

Avoid the penis: If Mom is putting her teen on birth control, that means there is a penis to be avoided. A teen has to go to school and learn stuff, has to sleep, has to eat food, has to drink water, but never has to do sexual activities (that lead to "someone comes in you"). Life is perfectly normal without the penis and the come. However, Depo-Provera does a great job if a girl absolutely cannot avoid the penis.