At what age did you begin providing regular social interactions with other children?I will say "from birth" and then I will ask you to replace "other children" with "other people."
Tadaa!!!
Your problem is schoolish.
You're believing that five year old girls need to play with a dozen other five year old girls. If you turn 180 degrees away from the myth and fantasy of how many friends kids have at school, and look at the real world in which you plan to live, things will look different.
Find people to visit, find places to go where other people will be. Begin to see people as people, rather than as pre-schoolers or school-age, or second grade. Just practicing that will take you MUCH nearer to peace about interactions with other people.
photo by Roya Dedeaux