So I just turned 25. While I could be happy about the fact that brain performance tend to be at its peak at age 25 or so, I am just super anxious that it all will go downhill from here.

I feel like I have wasted my childhood and adulthood (e.g. I learned playing piano and German, but just the basics. I would love to learn more but am afraid it's too late to really excell in them)

I'm kind of freaking out thinking about all the possibilities that are slipping away. I know it's not that bad, and decline happens slowly, but it still gives me anxiety. What can I tell myself to be more relaxed about this?