Why doesn't 22-25 yr old guys seem that old compared to me?

I remember when I was like 15, the 22-25 yr old guys always looked really old compared to me and also seemed really scary to me because I used to feel what if they bully me. But now I am 20 and guys of that age range don't seem that different compared to guys my age and I don't even fear them anymore. I feel it is possible that guys of that age rangr would rather be my friend now too compared to when I was 15. Why?