How can I find out if I am asexual, afraid of intimacy or both?

You can try to identify what part of sex makes you so worried or afraid, and then ask yourself: if this thing didn't exist, would the act of having sex attract me? Or again: is there any aspect of sex that attracts me at all? If you realize that you would like to have sex if it wasn't for that specific thing you fear, or if there is at least something about sex that attracts you, maybe you are not asexual. Asexuality is not just about not wanting to have sex: it's about not feeling sexual attraction at all, regardless of your will to act on it.