Everyone I know seems to have a solid group of girlfriends that they've known since childhood or secondary school days. They all prioritise this group of friends over other friendships and any other friendships are therefore an afterthought and come second place.
We moved areas when I was 12 and I lost touch with childhood friends. We didn't move to the friendliest area and I struggled to make friends at secondary school. I did make one friend in the end but she was, looking back, a frenemy.
I do have friends now but I know them all separately and as I mentioned they all prioritise their main group of friends over their friendship with me. I also feel that those who have that good base group of friends have others that are desperate to be friends with them too, whilst if you are like me then no one particularly is bothered about being 'in' with you.