Asexuality

http://fuckyeahsexpositivity.tumblr.com/post/92914532539/syekick-powers-demigray
There is sexuality, and there is romantic attraction, this table could help you understand better what that means. That said, it's not uncommon at your age to, how can I put it, think of sex as an abstract idea you don't know how to approach in practicality. It can depend on your upbringing, too.
I hope that crush is in your past, building such an amount of emotion for someone you aren't involved with, is bad for you.

I think that nobody has been able yet to wake your sexuality. I saw this site on a forum - http://www.asexuality.org/home/ . I hope it helps you to clarify your doubts. If you want to talk, you can message me.

Not all asexuals are sex-repulsed or unable to become sexually aroused. You can be horny and you can masturbate and still be asexual (there have been studies done that actually show no difference in rates of masturbation between ace and non-ace folks). Many asexual people even have sex, if they are not sex repulsed or want to please a partner or just enjoy the feeling even if they aren't sexually attracted to a partner or want kids or any number of other reasons. If you lack sexual ATTRACTION (which doesn't necessarily mean 'I never ever ever want to have any kind of sexual experience ever' and is more along the lines of all people are sexually 'meh' and sex is not a factor in attraction, there's no thought of sex or no 'Eyyyyy I'd like to tap that' when you're attracted to a person) asexual is a good label for that. It sounds to me like you very well could be asexual. I am a sex-disinterested asexual and would be happy to answer any questions if you have them :)