I had a lot of fun in my 20s and don't regret any of it. There are certain things I would have only wanted to do at that age and don't have a desire for anymore - like live in a small apartment in a dense city. I'm glad I had experiences like those then. So I guess I'm saying do what feels fun and natural now, and try to do a wide range of it. 

**But also**...! Start developing discipline and foundations that will serve you later. I only got into a solid, regular exercise routine recently and it has been such a life-improving change. I wish I had started sooner. There are whole categories of healthy habits and willpower-building activities that I sidelined in my 20s because they seemed dumb and "overly traditional" or something.  
I view those as misses now. The lesson there is to take seriously a lot of conventional wisdom and "widespread, boring advice" like exercise, healthy eating and good sleep. You probably *don't* actually need those things now to feel good - I definitely didn't! - but going into later stages of life with solid foundations in personal resiliency and health is a cheat code.  
You're already a few steps ahead by asking "nostr elders" for advice 👍

Also, read Marcus Aurelius and other stoics.