I'd like to join TonyWK in welcoming you here. Frankly I'm not sure 'asexual' is quite the right word. It's true you have not enjoyed your past encounters, however enjoying intimacy is a very fragile thing - no matter how it is portrayed by friends and the media.
Perhaps I'm misunderstanding but you seem to have had encounters because it was expected, not because you enjoyed it or looked forward to it. Plus you are uncomfortable with such matters on TV or the movies. Perhaps for you that has not been the ideal way to do things.
As someone who suffers from anxiety I can imagine that all the pressure that has been on you, plus not meeting the right person, has placed you in you current state.
A couple of ideas you might like to comment on - do you think you could mention this problem to your doctor, and see if the social anxiety can have more effective treatment?
The other is do you think it might be OK to simply go your own way? Do what you want for now. And if that means not engaging in sex with anyone then that's fine. There does not have to be anything wrong with you not to want sex. Maybe in the future you might , or might not. Find out about yourself in circumstances that are not pressuring you and making you hate the act and feel unhappy with yourself as a result.
Having reached 24 you will have an idea of a lot of things that do not work, in time you may discover different however there is no obligation - or hurry.
You sound a lovely and thoughtful person (and brave coming here) and people will like you simply for yourself .