By 30, I knew something was wrong. Then it was all downhill for me after my mid-30s.

I don’t know what all this shit is about peaking at 50.

Firstly, everyone is different and also what worked for one person in their 20's may not work in their 30's. Don't write yourself off, find ways to try out new things and new methods of learning. You can still do lots of cool things.