My introvert ways are costing me my teenage years.

Hey there! I’m 16 and almost my entire life I have been introverted. A year or two back I managed to be quite extroverted and gain myself a couple of “friends”, who didn’t last that long. I’m in high school now and I feel like I’m missing the best years of my life, because I can’t make friends, even though I want to. I try to initiate some conversations either face to face or through texts but I always run out of things to say and never really get anything from it. I see many people my age go to parties and actually get to be teenagers while I’m stuck here with myself not getting invited anywhere and always listening to the same music on repeat. How can I improve my social skills? and how can I initiate and keep a conversation going correctly? Please be honest! Thanks a lot!