Your DD sounds very much like mine at that age, early and verbose talker, self taught reader by 2, sitting on the sidelines at pre-k making daisy chains while the other kids played wild running games with each-other, lining up her toys just so, lining up pebbles for hours during her sisters' swim lessons etc. She was also diagnosed gifted at 5 and we had many comments about how very gifted and ahead she was in every subject across the board. She seemed happy enough and she was popular in that other kids liked her (although she was mostly indifferent to them), she would interact and play with a couple friends here and there but she really didn't ever seek that out.
We didn't discover she had AS or ADD until she was 17 and severely depressed, without any friends, lonely and failing in school (despite extremely high test scores in all subjects). I dismissed AS for her at first too, based on the checklists but then I learned how girls present so differently.
I highly recommend becoming familiar with the checklist for girls and keeping an eye on your daughter. Girls typically are much better at masking their symptoms and they tend to obsess over things that are more under the radar like horses or reading or astronomy. I recommend the book "Aspergirls" by Rudy Simone, it was a real eye-opener for me. There is a checklist on her site but it's more for adult women, you may recognize the traits in family members:
http://www.help4aspergers.com/pb/wp_c412f5cb/wp_c412f5cb.htmlI am not sure much would have changed for my DD at your DD's age with an early diagnosis, but it would have prevented a huge amount of stress and suffering for the whole family if we had known about it by middle school when the issues began causing problems.
