They just are.
At school, I had a couple of friends who were v wealthy (I’m average middle class I’d say 🤷🏻♀️)
I also had a couple of friends who were beautiful, but most of my friends throughout my life have been similar age, background and attractiveness. I love mixing with different people of different ages & nationalities and it’s never bothered me before.
Now I’m mid 40’s and starting to feel a bit differently. I had my dc a bit later due to infertility, so my new friends are average 6-10 years younger. They’re all better looking and they all have more money etc. I’ve never been made to feel any different, but am starting to feel it now, whereas at 40, it didn’t even cross my mind.