My best friends boyfriend has a very fat penis and she said it was very painful for about 6 months. But if you stick with it it will get better.
Little concerned of your age. I only felt ready for sex at 17 and with someone I loved very dearly ( still with him )
i am not doubting your love for you boyfriend i'm just concerned you are perhaps rushing things. I know a girl who didn't have sex with her boyfriend for over a year.
Don't feel you have to because he did. Hope everything goes well for you.
Sorry if I got things wrong.