So I know that i'm attracted to girls and all my crushes have been girls but honeslty sex disgusts me most of the time. I feel like I identify with the demi sexual but i don't know if thats correct since i've been calling myself a lesbian. Does anyone know what this would be called?
Demisexual describes how you're attracted to someone (or not attracted to them), not who you're attracted to. You can be a demisexual lesbian, you can be an asexual lesbian. Being a lesbian is about more than sexual attraction, it's about romantic attraction too. You can be a lesbian without any sexual attraction. If you're attracted to girls and you have crushes on them, and you don't have an interest in men, you're a lesbian - it doesn't matter if you don't want to have sex with them, or if you want to wait to get to know them better before having sex.
It's called being a sex-repulsed lesbian. This is unrelated to the asexual spectrum. Sexuals can be sex-repulsed, and asexuals can be sex-positive. Sexuals can have low sex drives and asexuals can have high sex drives (as a bodily function/masturbation interested only). Demisexuality is more about having ZERO attraction to anyone you have not known for years. It's not the same as disliking sex. And personally, I don't view demisexuality as a real sexual orientation, It's more of a preference, like how being attracted to casual sex only or people who wear glasses is not a sexual orientation either.
Demisexual is usually considered to be on the asexual spectrum (greysexual, demisexual, asexual, certain degrees of the above, etc.). You can be romantically attracted to the same sex and still be demisexual. This is often referred to as homoromantic demisexual (for example, I am a biromantic asexual). However, sex repulsion doesn't necessarily mean that you are demisexual. As Creativemind pointed out, you can be a sex-repulsed lesbian and a pro-sex asexual. Demisexuality applies to people who do not experience sexual attraction until they have developed a strong emotional bond with their significant other. If you feel you fit the description of demisexuality then by all means you can be a demisexual lesbian.
You say that sex disgusts you most of the time... what do you mean by "most of the time "and what is it that disgusts you about sex? I notice you are 15, so I'm guessing it's something about the thought of sex that disgusts you... can you say anymore? At this stage I would just allow your feelings to come and go as they will and try to understand what might be causing these uncomfortable feelings about sex. Don't rush to pin a special label on things because it can actually create more confusion than it solves.