But again, bringee, you are choosing to let a narrative from your childhood dictate your attitude to making friends in your 30s.
I'm from right down the bottom of the non-coping working class we lived by a traveller halting site by a landfill site, and the travellers wouldn't play with me at school because I was 'settled', and the settled kids didn't like me because I was quasi-traveller from their POV, and into the bargain my closest childhood friend came from an upwardly mobile family and was encouraged to discard me by her parents when they made a lot of money, moved away and she went to a private secondary school and started to hang around with girls with ponies and ski holidays but I don't let that fairly shattering set of experiences in my schooldays define me as an adult.
A pp's suggestion of talking to a counsellor about it sounds good to me, if it's something that is still dictating your feelings about friendships.
And I agree with the same poster's advice to not cut off your current friends if the only issue with them is a lack of interest in your children -- if you still genuinely feel a bond with these people, the friendships may reignite properly again in the future, when your children are older.
I have a child, but my friends and I are not that interested in one another's children, and I certainly never remember birthdays -- my friendship is with the parent, not the child, and while they were in a very baby-focused phase, I was just waiting for them to re-emerge. And vice-versa.
And this is key to the whole thing --
It's just genuinely never occurred to me to take class into consideration when deciding if I like someone or not.
not the class part, but focusing on whether you like someone you meet or not. Your posts are about worrying about 'not having enough friends', which makes it all sound weirdly impersonal, like worrying about not having enough nappies stockpiled or something. People don't want to be mechanically snapped up as just another item to add to your friend stockpile are you meeting people you like and want to have in your life? Focus on whether you like them!