Joking aside, I don't think young people should listen to older people.
Yes, it would make life easier for older people if they did, but I think for the progression of society and life it's important to find your own way, warts and all.
I don't have any children. If I did I would tell them not to climb and jump out of that tree. I would tell them not to cross that road and go beyond the block. That would be the responsible thing to do.
But I would be sorely disappointed if they obeyed me. Every ounce and fibre of my being would hope to God they disobeyed me and did it anyway without telling me.
Similarly, I could tell my younger self any amount of truisms, but it's absolutely essential that I wouldn't have listened, even if I had been nodding my head in agreement.
Facing adversity and difficulty and overcoming them is essential to our development, and being obedient and doing as others say (sorry, advise) doesn't help that.
There is nothing I would tell my younger self. No advice I would give.
Actually, maybe just the one - it doesn't matter, you always get another chance.