Why is it so difficult to make new friends in adulthood?

Some of my high school peers are either married or have children of their own. Some are in relationships so they don’t have time for me anymore. We do see each other but it’s like 2-5 times a year. I only talk to a couple of friends more now because my other friends are distant or don’t text me much anymore. They’re so busy with their children and a lot of things. Me, 26, single, working and starting college soon. Dating sucks for me. I give up. I also give up on making new friends. I’ll just stick with my old friends and not meet new people anymore. They’re the only ones that kept in contact with me. My mom said I should just stick with them and pay attention to them. Some women give me dirty looks since I’m a very tall, slender curvy woman. Being a 6’4 woman in a would of normies is tough.

Why is it so difficult to make new friends in adulthood?
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