might be a sensitivity issue. Something I would suggest seeing your gyno. doc. about to rule out any medical issue that might be affecting you.
When you have a honest to goodness orgasm, you know it. I didn't cum until I was about 20, well after I started being sexually active. But it was not a medical issue for my body, rather, it was lack of understanding how to stimulate myself (aka all I needed was more focus on my clit) And I started masturbating with a vibrator. My doctor explained it to me that basically, sometimes you have to teach your body to have a full orgasm.
Once I got that down, I've been cumming very consistently since, sometimes two-three times in a sex session.
Also.. girl... please please please change that horrid red color of your front, it's giving me a headache.
anyway, in short, see a doctor about it if you've exhausted all the options of stimulating yourself without much affect.
sweetpea