Personally I cannot reach orgasm without penetration. Never have been able to. I don't think it's the feeling as much as feeling close to my partner.

I had my first orgasm at 17 also. It was like....it felt good and all.....but then I actually had one.....I'll never go back! And now that I'm almost 24 I have discovered exactly what has to happen for me to get there.

I think it's all about experimentation. Masturbation allows you to discover your own body and what you like. How are you supposed to have someone else get you there if you can't do it yourself, y'know?