I feel for you. I found that when dd was 3 (now 5) finding a good social fit really hard. Harder than at any other time really. She just couldn't find her place. It has gotten easier as both she and her age peers have matured. She still has little in common with them, but she can at least communicate with them and they have a general idea what she's talking about. And she has a greater tolerance.
I think you mentioned in another post that she was displaying an increased level of tolerance - which is great. However I know for dd there is often a consequence to increases in 'public' tolerance and that she then becomes more emotional away from that environment and it becomes necessary to find other intellectual and emotional outlets for her. I really agree with all the advice you've been given so far, but the piece that rang true for me was needing to be her 'friend' in the sense of sharing her interests etc until you find yourself in a circumstance that is a better fit. Dd is really at her best when she's with adults and she feels she can be herself.
Good luck. And don't be too hard on yourself - you can only do what you can do. All your recent posts show how dedicated you are
you can't do much better than that!
