How do you build self-esteem (especially with girls)?

HI! I'm a 20-year-old guy, I'm studying cinema and for this reason my parents often reproach me for my choices ("Couldn't you have chosen a serious university?" or "Couldn't you have been interested in medicine or physics?"). This already makes me feel bad. I have interests in art, cinema in particular... but I know perfectly well that I will hardly have a future in this area, because few do.

I work in a nightclub. Basically, discos have always intimidated me and I've never been comfortable with them. However, I decided to look for a job in a nightclub to deal with this feeling of unease. Now, I suffer less from the environment, but I can hardly speak because I have a stutter and loud music only makes it worse. I wanted to look for a job as a waiter in a normal (less noisy) place. In August I go to work in a club.

Regarding girls, absolute zero. I don't think I'm too bad, I'm tall (about 188) and I keep very fit. I don't think I'm ugly (sure... I'm losing a lot of hair though). Girls don't figure me out, except the ones I'm friends with (who often talk about the "cool guy in class" or the "cool guy they're hooking up with"). In short, I hardly ever see girls interested in me, and I often have very low self-esteem.

Perhaps this was also caused by a childhood friend of mine, who was (and is) very handsome. We often went on vacation together or went out on our own business, and every time there were girls who turned around and asked for his number. He then got engaged to a girl and stopped calculating me. He was one of the very few friends I had.