DD1 went to MS preschool. I saw there, that she would always be loved and adored by the children around her (she is very winsome) but that she would never have friends because they would always mother her. That and the attention issues that meant that she would need considerable support just to keep her in the classroom. Now, as she is, she may be able to cope for short whiles in a MS classroom with lots of support.
At SS she is supported in small groups successfully - the site is secure, they have CCTV and plenty of staff. She is able to take the register to the office then return to the classroom, for example.
At SS she has friends. I mean real, peer level friends. One of those friends had a birthday party last night. DD1 is very poorly but insisted on going. She sat on my lap, watching her friends play on the soft play equipment.
School does not have to make special adjustments for DD1. Well, they do, of course, but because they make them for all the children, she isn't isolated by it. Sports day, for example, is a mishmash of children who talk but don't walk, children who talk and walk, children who walk but don't talk, children who use standers and kaye walkers, etc. They all join in. They all do what they are able to.
DD1 has to learn to count in larger numbers. I saw her being led around the school, seeing how many coats she could count. Real, practical ways of learning, which can be done because they have the time, resources, expertise.
Go for it.