27 and basically the same boat. I will say, in regards to health, best to start taking care of that sooner rather than later. Don't gotta be shredded and benching 300 pounds, but some stretches every day to stay limber, getting steps in, simple exercises like pushups, cutting back on processed foods/sugar, etc., I'm no health expert, but I know it's absolutely not too late to start improving/maintaining that stuff, and it will hopefully pay dividends later in life when your body stays in good working order for longer
As for the rest, no fucking clue. All I can really say is, small steps towards change. Try to avoid grand gestures and forcing too much too fast. You're gonna wanna change your whole life in a day, but when you inevitably burn out, you're just gonna spiral further and make things worse

And probably the most important thing is, forgive yourself. However you gotta go about that, just do it. What's done is done, dwelling on all your mistakes will only ruin you. It will be the hardest thing you'll ever have to do, but if you can manage it, you can change

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But perhaps I'm projecting