We have a 10 1/2 year old daughter who also is an Aspie with ADHD as well. The clothes and fashion issue has been very prominent as of late here as well! My husband and I are very "jeans and t-shirty" as well. I was in the military a LONG time so I remained this was-not girly girly either.
Unfortunately for us, our daughter began "developing" at 9 (has also had to wear a bra for 10 months now). She has always wanted to wear dresses,etc. In those last 10 months though she has not adjusted properly (as far as shirts too tight and dresses too short or even weather appropriate choices)but, like you guys, I want her to have her own sense of style. So I came up with a strategy. Every Saturday, we go online together and print out the week's weather forcast. We then go to her room and play a "matching" game. Sticky notes labeled with the day of the week (including that day's temp) are stretched across the floor. First, each day gets a pair of socks, then each day gets underwear, then bras, then pants/leggings, and finally shirts/sweaters/vests/dresses. Then we pick up a pile. We say "It is going to snow and be 20 degrees today, do you think you will be warm in this?" This makes her stop and think "should I wear shorts on a day that snows?" If she answers yes (which after the first week of doing this, that stopped), then we go back to the computer and look at pictures of people in our area....she observes and then changes her mind. Every few months (or when I see a noticable change in height or weight), we conduct a "fashion show". She tries on all of her clothes, it gives her the chance to feel ambitious about her style, PLUS it lets me know what clothes of hers are starting to not fit. We create the "help another friend" pile of clothes that no longer fit, and then go together on another day to our Goodwill store and donate them...also she can peruse the racks for other clothes she may like. Sorry for this being so long, feel free to email me if you would like or facebook me. :-) have a good day!

ASD = Autism Spectrum Disorder

This is one of the positive developments we've seen in my DD over the past year. She used to hate dress-up and was really into stereotypically "boy" things like Thomas. Recently she has turned into a real girly-girl and loves Disney Princesses like a typical preschool girl. Anyways, in terms of your DD since she's older, I would suggest American Girl's "The Smart Girl's Guide to Style" by Sharon Cindrich. Kiki magazine is an age-appropriate fashion magazine for 'tween girls (unfortunately "Seventeen" has become way more risque than it was back when I was a teen so I wouldn't recommend that).

Thanks. Want to sound knowledgeable

Sorry the computer changed my meaning