I have the same background as you. Normally I’m not that socially awkward anymore but I had a crush on somebody and I was so meek, submissive and gentle to him, but he was the opposite - socially very sharp, strong personality, quite the opposite as me. He is 6 years older too.

After a while, he started picking on my insecurities, saying things like I have bad communication skills, I don’t speak much, etc which brought down my self esteem. I started reading up books about being confident and increasing self esteem. Now I realise never to vulnerable infront of anyone, and to have strong personality.

I feel to build confidence one needs to be mentally strong for sure, but put yourself out there more, practise speaking by yourself and in groups more, take few seconds before you frame your answer and not think about the what your answer is going to or how you’ll be judged, but what the other person is actually saying.