Is it safe?

So, recently, early November I would say, I got a Depo shot (it’s birth control).. and they told me to wait two weeks to have sex. Which I didn’t... BUT! Me and my boyfriend was smart to be safe at least

Anyways. He want to finish in me but I’m scared of the outcome (no pun intended?) like yeah I’m on birth control and the doctors and online says it’s 99.9% effective, like it’s works but I’m honestly so scared to let him finish in me. I’m only 19 and I don’t wanna be a mom lol