I would probably tell my younger self to get serious and finish what you start, because maybe then I wouldn't have dozens of half baked stories with less than two paragraphs rotting away in my Google docs. 🤣🤣🤣
I would also tell myself not to write on paper, because you'll never get around to digitizing them like your tenth grade creative writing teacher suggested.
But in all seriousness, I would say that the most important opinion you'll ever receive is your own. Critic and reader feedback is all well and good, but if you don't like what you're writing, it's okay to change the direction. Don't worry about what other people will say, because the betrayal of one's own soul is the most heinous betrayal of all. Good luck, and happy writing!
Aesthetically yours,
Tubacabra