Never Orgasmed

I'm 17, a lesbian and have only ever masturbated. I have never had sex with a partner. I remember starting to masturbate really early, around the age of three and four. I masturbate about twice a week and in all those years I can only think of about one time I ever MIGHT have orgasmed. I just kind of finish, I kinda get a release but it's more like my nerves jump to a hundred and than just drop in a second. Everything I read says that's not really an orgasm and I don't think it feels like on either and it doesn't necessarily feel AMAZING. It's more like, "Oh, Okay, guess I'm done.". The one time I think I orgasmed was a couple years back. It felt really good and I was giddy after, but I never have experienced that again, no matter what I do. Again, things I read say, "If you really orgasm, you'll know!". I don't know though, maybe I'm just not someone that can orgasm or maybe I just need to experience it with someone else before I can. What are your thoughts?