If I had to guess, assuming you're physically healthy, I'd say your social anxiety is coming up with reasons not to get in a relationship.

It's "gross" and you "missed that development."

Most cases of asexuality (again, barring any hormone problem) are marked by intense fear of intimacy.

It may be helpful to talk with a therapist about what specific fears you have and where they may have come from.

Good luck. Deep relationships with others are the best parts of life and I hope you don't dismiss all that because you feel different right now.