21 and socially inept

Hi, Im 21 and ever since my freshman year of high school I havent had a close group of friends. All my friends left for other high schools and I did not talk to anyone the remaining three years. I feel like I have missed out big time on socializing and now I’m just socially inept. As a women, I feel like ppl expect me to be a little bit more open to conversation and sometimes even carry the conversation, but I simply cannot. I do not know what to say, I’m constantly overthinking, and I don’t want to focus on myself in a conversation but sometimes I just can’t focus on what someone else is trying to say and I give out very lame responses. I find myself constantly avoiding social interactions bc I get an immediate fearful reaction when thinking of starting a conversation with anyone. With missing socialization, I feel like a I’m still 15 and more immature than others. (although I would say that 15-year-olds have better social skills than me). Idk how to banter and follow along with jokes anymore. This problem of being socially inept has become more of a problem for me since Im doing research in college and I cant help but think that grad students I work with must feel like they’re taking care of kid that can barely follow a conversation and does not speak for long stretches of time. Also, it does not help that my mom expected for me to be a social butterfly like her and rubs in how she would constantly go out when she was younger, have various boyfriends, and how easily she can make friends. Anyways this is convoluted and more of rant than anything but I just wanted to let it out since I have been thinking about my situation for a while now.