Of course. Everyone has regrets. And everyone learns (though some people keep making the same mistakes). But would I do things differently? No. Sure, sometimes I think about the past and kind of wince, thinking "If I could just go back in time and take that opportunity/stop myself from doing something stupid/kick that person in the crotch/etc., things would be a lot better." But if I never screw up, how will I learn? If nothing bad ever happened to me, how would it strengthen me? What kind of stories could I tell if everything was hunky-dory all the time? So maybe I jumped in a time machine, barged into my room in the middle of the night, and told my younger self how to handle a situation. Maybe things would have turned out better. Maybe not. But if things had turned out differently, who knows how my life would change.
But you know what? I like the life I have now, despite all that past crap. I have my own house. I have four amazing fluffballs, and I don't mind being their slave (most of the time). I have good friends. I'm employed. I never made a lot of the mistakes that I see people make all the time. I never got arrested. I never got addicted to any questionable substances (all my addictions are purely psychological). I never had an eating disorder or let societal pressures overwhelm me. I never jumped into a relationship or marriage. I never got pregnant. I'm not wasting my life away in a dilapidated shack with screaming children and a miserable marriage, wishing I could go back in time and kick myself in the head. I'm free and secure, and I still have a few years of youth left before time starts smacking me around. It's not a perfect life, but if it was perfect, it would be boring. The past is the past, and what's done is done. All I can do is move forward.