That sounds Avoidant to me. The things you mention sound a lot like me, although I open up more to people now. I suspected I was Avoidant for a couple of years, and just got diagnosed.

I don't think there's anything wrong with being introverted - I think introverts are social in their own way, we just do it a bit differently than extroverts. The problems with AvPD lie in the wanting without doing, the lack of confidence and assertiveness, the self-doubts, etc.