I am 24 too ! I was scared of the phones but in July, I went abroad for a new job, and I have done two weeks in quarantine in an hotel where I should order my food by phone each day for the next day. Could barely touch the phone at the beginning, I was stressing about it each day, 2 or 3 hours before calling. At the end of the quarantine, I even forgot sometimes that I already called the room service. Same to order in the restaurants : I was doing most of my meal at home before, and now I go often outside. Was scared as hell, but no it doesn't affect me. Same for online meetings, stressing days before, and now I am the one that set them. My conclusion is just : put yourself in unconfortable situation by purpose. If you have the choice between going to see a person versus calling her, call her. If you are in a supermarket, ask someone where is X, instead of looking around for X. If you are ordering food at the cashier, order the food that you feel you will have the most difficulty to say. In really few times you will have improvments ! And to jump into uncomfortable situation, in my mind I was speaking to myself : "Just f*ck it, I already stuttered in front of hundred of people, and I will still stutter in front of severals more, + I will have forgotten this exchange in some days, what the point ?" An another advice : write down on your phone each accomplishments you made, and if you feel stressed before a new "jump", read them multiple times, it will give you courage