This is us too. We were 100% set on unschooling, and in fact I still *feel* like an unschooler and I absolutely support that philosophy and lifestyle and I want to even still call ourselves unschoolers, but I'm guessing that wouldn't fly in some circles since DS is going to pre-K this year.
Our story--last summer we had DD and after a few months of dealing with a rough pp recovery both physically and emotionally, we decided to put DS in a 2x a week preK that was play based and very low key. He needs a lot of social interaction and activity and I could barely walk across the house without feeling faint for the first month and a half pp, and a long time after that before I could get out of the house on a regular basis. It was meant to be just for that one year so DS could get some activities, play with other kids, etc. and give me more time to rest and recover and work through some stuff.
Then this summer we moved across the country and it has been very hard on our whole family. The reasons for putting DS in preK again (3x a week at a Waldorf school) are many, but none of them are for educational purposes

The best way I can describe it is that given our current situation, this is the best way for everyone in our family to get all of our needs met--for DS to have the social interaction multiple times a week, make friends in a new place, and to give me the chance to get some rest and take care of myself (still working through lots of pp stuff).
We also felt like Waldorf was a really great fit for our family and our unschooling philosophy at this point in time. The program is totally play based, not academic at all. I think a lot of the things they'll do at school will be really great for DS (we think he has some sensory integration issues and a lot of the things like kneading bread, lots of outside physical play, etc. will be really good for him). They have lots of oral stories, painting and crafts, lots of free play, etc. He is in a small class so I think he'll have the chance to really make some friends. Plus as a bonus I'm hoping I'll make some new friends through his school as well.
I'm not sure if we'll send him to K next year. I sort of hope not mostly because I really want to completely unschool and that is exciting to me, and because the Waldorf school is so expensive. We won't send him past K because once they hit first grade the program isn't as play based and free as we would like. To the OP, you might want to look into Waldorf in the grades more before you decide, though obviously you have lots of time. While I feel like the Prek/K really fits with unschooling for us right now, I didn't feel the same way when I looked into how their grades work. From what I understand the grades are actually very teacher led, copying from the board or what the teacher says word for word, etc. That's not to say there aren't wonderful things about Waldorf school beyond K, because there is a lot I wish I could pick and choose! But the overall format is too structured and teacher led for us at this point. But again, you have time to figure that all out and I know for us I am just trying to focus on what is right for our whole family right now, and we'll figure the next year out next year

It is hard, I feel like a little bit of a fake. I wanted to go to an unschooling conference near me this summer but felt like it would be weird since I'm sending my 4 year old to school, you know? But I really *feel* like an unschooler. In many ways I feel like this waldorf program isn't school at all, but more like a 3xa week playgroup that I don't have to stay and watch, you know? It is kind of like being caught between 2 worlds and not really fitting in with either. I want to make some unschooling/homeschooling connections here, but what will they think when they find out my son is in school? Plus I know our families think we are finally coming to our senses and next year or the year after when aren't in school anymore they're probably going to give us a hard time. Not that it matters, but I'd rather not have to explain things all over again or face that kind of discouragement.
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