I can relate to how you feel, I'm very similar however I think my quietness comes from school offering the wrong answer. But now I too, worry about feeling stupid if I say something so I don't say much to anyone.

Your mom probably doesn't say these things to hurt you, she may even ironically be showing how much she cares. Parents often see their kids doing silly things as cute and that's why they share it with their friends. I think you should try to talk to her, and maybe talking to a counsellor can help you find a way to approach that