Hello,
This is interesting because I never thought about something I can't change and that is the past.
If I could go back I would tell younger self the following things:
1. Stop waiting for dad to give you approval, he's not going to. You'll find this out when he is three weeks away from his death. He is a controlling individual and you can walk away from his influence. You don't need his approval to suceed. You only need yours and the belief you can.
That's what I'd tell myself. I'd want to stick around to help my youngerself get free and start living instead of believing what everyone else believed.