Interesting post. I have been impressed before at what I've heard preschoolers come out with. They are bigger thinkers and often smarter than people give them credit for.
The things I would tell my younger self if I could:
Don't judge yourself so harshly and don't beat yourself up
mentally over things (still working on this but I'm better than I was)
Don't be so quick to judge others. You don't know the situation they are truly in
Save more money while you are living at home and aren't paying rent etc. Life is going to get harder
Invest some of that money you are earning while living with your parents because your future self would have thanked you if you had have done that
Get help if you need it
Children can see things more clearly then we do sometimes. Thank you for sharing your list of advices to your younger self.