Unfortunately some women just have difficulty getting orgasms. Can you get yourself there? One thing that might help you is suggest different positions, foreplay, etc. You might also consider using a toy, although you're only 17 you would have to wait on that unless someone got it for you. Anyway a different position can make all the difference in the world, don't be afraid to try new things or suggest new things. Also one of my friends swears by .. Trojan condoms "for her pleasure" I think they're called. Anyways she said they're amazing- so try new condoms too. There are lots of things out there with different textures and what not. (Although personally I suggest NOT trying the heating ones... just don't. It's not pleasant.)
If you still have trouble getting there I cannot give you much hope except -I noticed that age makes a difference on my body. It's much easier for me to have an orgasm then it was when I lost my virginity. And I know it isn't all because of the difference in partners because I had a fling with my high school ex only a couple years ago- and I know he didn't become some kind of sex god between the 3 years when we broke up and when we got back together. Second, while my best friend cannot have an orgasm normally, she gets them very easily while pregnant. (Not that I'm encouraging pregnancy, just saying potential future hormonal changes could help.) Finally I know a girl who only was able to reach an orgasm with a guy big enough (which is why I suggest a toy, perhaps your partner isn't large enough for you).
It might be a little tricky to figure out what is needed for you to get an orgasm, but have hope. Usually once you figure out what is needed it makes it a little easier to get to.
Don't worry about it.The more you worry about that in the moment, the less likely you will get there.
I hope I'm not stepping too far out of the box here but my personal recommendation is that you do some self-exploration. Once you know for yourself what works for you, it's much easier to adjust and/or assist in those moments. Female orgasm is somewhat complicated, partially because there are several kinds.
Above all, be safe!
It's normal dont worry. I lost my virginity at 15.. very young... I kno I'm but I was dating the guy for two years at the time. And I didn't have my first orgasm with sex until I was 17. Make sure you use condoms, and get on birth control so you do not have any scares with pregnancy as you are to young. But try having him rub your clitorus. Or try spooning and him play with you while having sex. Also you try riding so you can go the speed and depth that suits you.