scared for sex!

I'm 15 and I've sucked dick before. great introduction, right? lol but I've been pretty sexual with various male partners but I've never had vaginal sex. I have a boyfriend now for the past almost 3 months and I'm scared to have vaginal sex. not nervous about the pain or an STD but nervous about getting pregnant. I understand the use of condoms but they still seem kind of sketchy. I personally believe that I am emotionally and physically ready for sex with my partner but the fact of failed condoms and possible mistakes made during penetration seem to worry me greatly. any advice?

thanks guys ((: