How can I believe in myself?

I’m not going to go into huge detail (because it’s deep) but long story short, my biggest lifelong goal is to become a successful musician. I tell myself every single day I will never ever be able to do it. I have no talent and feel constantly like I have accomplished nothing, despite being only 18. Self doubt is crushing both me and my dreams and ends in me feeling quite down all of the time. I need advice on how to aim high, have confidence and finally believe in myself and believe I’m capable of whatever I dream of