How can I live with myself?

22, got sick in middle school, didn't recover until adulthood, then a combination of bad luck, terrible events, and, most notably, atrocious mental health, has cost me my transitional years (18-22).

I think I actually have a chance to finally start my life, but it's far, far too late. I'm at the age I should be graduating college, not starting. I'm not sure how to cope with all these lost years. I feel like I stopped maturing at around 18 or so, and all the "growth" I've undergone since then has just been learning to be semi-functional (as in, learning to stop self mutilating on a weekly basis) rather than learning how to properly be an adult. Now it feels too late to start. And yes, I know the BS saying that "it's never too late" even though it eventually is, and the BS saying that "comparison is the thief of joy" even though comparison is the only way to determine an individual's objective value.

So what now? Do I just accept that I've lost too much time to ever live a life I want, and just do the best I can with what I have to potentially do all the things I've always wanted to do even though I will certainly always be struggling with my mental health and considering ending it all, or do I just follow through, end it, and spare myself from the rest of my life since it can't be worth living anymore even though I will never get the chance to do anything with my life?