It happens to the best of us for numerous reasons, imposter syndrome, just feeling like it doesn't make sense, someone telling you it's wrong/invalid etc. It's okay if you don't feel like your valid. (Which you are!) You'll figure it out
That sucks, glad you knew your boundaries! No one should be forced to date someone, especially aro people! It's okay to lose attraction to people, and no one should say otherwise. Hope you're okay!