Scared and inexperienced. Pls help

Okay so I had sex with a condom and he came in the condom inside me. I was on no form of birth control but since we’re young to make sure we got plan b just in case bc it was my fertile window. What are my chances of being pregnant?? I’m kinda freaked out because im still new to all the sex and birth control stuff and still trying to get a handle of everything.