Group conversations: Quieter than the wall

I've always been quiet in group conversations, often unsure of what to say. By the time I think of a response, the conversation has usually moved on. I believe this traces back to my childhood, where I didn’t have many friends and felt more comfortable being alone. My mom, a housewife with no social circle, was always at home, which likely influenced me as well. As a child, I was very shy and hesitant to speak. Now, although I’m not as shy, I still sometimes struggle with saying the right things and often feel like what I say doesn’t make sense. Sometimes, I’m so quiet that people forget I’m even in the room. I believe that im a good conversationalist, but only one on one. This just makes me feel lile shit.