Why is it important to be married before having a kid?

My boyfriend keeps kind of pressuring me to have a baby. We haven't been together long. But we both want to have kids eventually. And honestly one of the things I've always wanted to be in this life is a mom and to experience motherhood... But i don't feel ready.

And i honestly wasn't taught any better growing up but I'm too afraid to ask anyone. Because i literally tell my boyfriend "why do you want to make me a mom so badly, but you don't want to marry me or want me to be your wife first?

This is my first healthy relationship (i hope it stays that way) but this is his first relationship, and sometimes it feels like i have more sense but he doesn't get where I'm coming from because he hasn't experienced. But I've seen it, not just in the experiences with myself, but growing up and seeing it in others.

I've told him "just because we have kids doesn't mean I'm going to marry you." Because i know marriage is hard and I didn't grow up with seeing healthy marriage or adults stay together, so i also feels like i don't see what he sees.

It doesn't feel right to have kids before getting married but i also know thats how things turn out sometimes.

I would like to be a mom and i know i would be ok if I ended up pregnant but part of me feels that is not the change i envisioned for myself in the near future.

Kind of venting but also need genuine advice without any judgement.