There's not a lot I regret about my past even if my past hunts me today and I as many others had a lot of painful situations.
I'm pretty obsessed with the idea of time traveling to the past, I'm not sure if I would fix stuff that I did, maybe I can still fix them today? Idk. But I remember when I was like 7 or 8 as the only "normal childhood" phase in my life, everything was so chill and normal, I wasn't bored and everything about life was simple, I want to return to that point of my life again very much. If I had the chance I would also warn myself about the person that abused me when I was a teenager, I'm pretty apathic about my traumas today, but the damage certainly had an effect back than and made me who I am today.