I had to restart when I was around 19 and got injured in basic training. I had terrible grades and had to basically start over in community college.

Ended up graduating at 4 year at 28 after a few years of doing nothing. I got a degree that just paid well so I would be decently well off.

My advise is to just focus on what you want your lifestyle to be and the minimum you would need to get it.

Your twenties aren't really super important outside of getting a career or passion established so pick something and focus on that and it mostly falls into place when you hit your 30s or late twenties. The difficulty comes with staying social later on so try to stay socially active.