There are two times I noticed I wasn't as good as before mentally. One when I was 17, I noticed that unlike when I was 12 I no longer could memeroize entire boo

There are two times I noticed I wasn't as good as before mentally. One when I was 17, I noticed that unlike when I was 12 I no longer could memeroize entire books. Which back then I could, I had memorized 12x20 Questions and their answers back to back. But now in HS I felt I'd forget 90% of what I read yesterday. Now to learn I had to write the thing down and act of writing helped me remember things. Second time I noticed is when I was 24 and still in college and when to study in a group. After 10 or so minutes, I had hit my limit with info from one page and just started to skim, but other students who were like 19, kept on writing things down in paper and weren't getting exhausted. I noticed lack of stamina... Now it takes me 3 months to read one book that I'm very interested in. Back then I'd finish a book in 3 days and write 8 page essay on it. So yea things change.