Pregnant At 17 (long post)

I will be 18 in 3 months and im just finishing up my last year of highschool. I was a virgin up until about 2 months ago when my boyfriend and i decided we were ready to have sex. We used a condom and everything went smoothy. I had also started using this app a short time before we did . My bbt started rising around when i was to get my period . I missed it and its been two weeks with no period. Ive been nauseous and had pelvic pain that i though was because of the zinc supplements i take. I also was sore on my chest and became  hungrier. Do you think i could be pregnant? I would love to have a baby but i know my boyfriend isnt ready to be a father and his family would be really upset. Advice?