Hello Basically To Get To The Point I'm 18 Years

Hello basically to get to the point I'm 18 years old and my girlfriend is 17, we have been sexually active for a few months now. I am a compulsive worrier . She is on birth control and claims to take it religiously we also use condoms at the same time both could be considered in the typical use factor. My main concern is the likelihood of pregnancy while using both forms of birth control. I have done extensive research on the topic but it still continues to bother me. I am seeking medical advice to ease my worries. Should I continue to worry like this or is just a waste and silly?