No, "most people" don't have kids in their 20s anymore (especially not their early 20s), at least not in the western world. Back when the economy was great and even entry-level jobs paid enough to live on, people got married right out of high school and started having kids soon after, but that's not how things are anymore. People say you're too young because you'd most likely have no way to financially support your child without either being on government assistance or relying on your parents. And we've made a lot of medical advancements and live longer than we used to, so it's now safer for women to have babies at a later age, and there's no need for people to rush and have kids young. So nowadays, people generally think that your 20s should be about having fun, figuring out who you are, and getting settled in a career, rather than being tied down to a family.