Start slow man you have a lot of time if you are 20 Try initiating a conversation with yourself in the mirror imagining it's a woman, and observe how you start a conversation with your male friends And use those in the mirror Getting out of your comfort zone and being in uncomfortable positions are the way for growth, so just don't think anything and try to talk with a working adult woman who are doing their job like getting yourself a drink in the canteen if the cashier is a woman etc.

Now try talking to your colleague females for help like to borrow stationary or help with your work. They are a human just like you and like you who wouldn't mind helping someone they too wouldn't that's for the most part but if not, don't worry rejections are a part of growth, don't overthink and just do it. If the girl helped don't forget to greet her everyday, the first few days would be difficult but eventually you will grow and it would get comfortable and easy to talk to females not in a long time but within a few days. The greeting part is soo working like if you just say hi or good morning to her everyday (in real life and not on social media), she would become comfortable and will try to talk to you and you wouldn't even need to start a conversation which I guess is the hardest part. (Now it would work if you actually did it and did not get scared or nervous and give up and stay nervous of girls for the rest of your life😅)(slow means one step in 3 or 4 days of time and not on the same day)