I wish I would have made the decision you are going to make when I was 15! I was a caucasion non-JW dating a Mexican unbaptized 16 year old JW. His parents gave him lots of grief. He thought the JWs had the truth but he didn't want to live it. He was dating me and we were sleeping together. We were in love/infatuated. He was my first love.
I asked him so many questions and he was so vague. He resented me asking questions because I think he didn't really know the answers and it made him feel like he should have answers. We had been dating for 2 years (friends for a year prior to that) and he told me if I really wanted to know what his religion taught I should just study with them and find out for myself. Big mistake!
Long story short I ended up studying with the JWs and we both got baptized together about 6 months to a year later. We stopped having sex when I was studying (that was hard!) and we ended up dating for about 2 more years. It was really hard. His family resented me when I wasn't a JW and then even after we got baptized they gave us a hard time saying we were too young to date and we either needed to get married or break up. They wanted all our dates chaperoned. I was not ready to be married at 18 and I ended up breaking up with him.
Through all the drama with his family and that relition he never stood up for me and our relationship. It really took a toll on our relationship and the worst part is after breaking up I stayed in that religion because I believed all the bullshit they fed me. Being in that relition caused me to cut off ties with my family and all my non-JW friends, give up the tennis team and softball team in high school, pass up all the school dances, graduate highschool early by skipping my senior year and doing independant studies instead so I could pioneer (be a missionary) in their religion, I passed up college, I got married too young, I ended up divorced and expelled, shunned by all my JW friends and a single mom with a child to raise and a major ulcer!
As others have said here... Run!!!
Please learn from my experience so you don't have to learn for yourself. I know how hard that can be but I hope you will stick to it and do what is best for you and your boyfriend in the long run. The odds of it working and you being happy are slim to none. I know you love him. It was the hardest thing for me to break up with my boyfriend when he proposed at 18 because of the pressure to get married. It took a year for our relationship to finally really end. You can do it. I should have run as soon as I found out he was a JW. Would have saved me lots of pain over the years.