My wife rubs her clitoris while we're having intercourse. Yes its a big turn on, and we all have to take control of our own pleasure.
If you're 19, and your boyfriend is of similar age, he might just lack the patience of skill to let it happen naturally.
And keep in mind, women do not easily climax from pure vaginal penetration alone.
Here's a suggestion. You might want to try having sex with him entering you from behind. You rub your clitoris while he gently massages and maybe even slides a finger into your anus. Normally I'd say ******* but this is a clinical forum. : )
We all have a large number of nerve endings in the anal region, and women just like men find stimulation of that area to be a wonderful addition to their sexual activity.
When I was a teenager I never masterbated. I didn't know my body that well either. Not until after I got married that I started. I think if you tried to masterbate, alone, you could figure out what pleases you and you might have more luck during sex. But, most women have difficulty with orgasim during sex. Once you've learned your body, you could start pleasing yourself during sex, guys love that! Plus, you're still young, I'm 26 and I've only recently been more intuned with my body and finding more and more things that turn me on.