If you are asexual, that isn’t going to change. If the thought of sex grosses you out, that may not be something you can do anything about. If even touching yourself seems gross to you, you may have to decide whether it is something you just have to accept about yourself or whether you want to try pushing past it just once to see if you could learn to enjoy it. But if after giving it a shot, you don’t like it, then I wouldn’t force yourself again.