The ski boot has no idea of a person's gender - it only knows the foot & body going into it and the physical forces acting upon it.
When shopping for boots, treat yourself (herself) as an individual who is nearly 6' tall, has feet that are 27cm long (semi-educated guess), relatively low narrow and low volume, etc. Ignore gender. Match the boot to the person.
The above statement from onenerdykid is correct, however may be jumping the gun a bit, assuming that she is truly a women's 11+
First of all understand that the boot suppliers can only be profitable when they build the fewest number of permanent steel molds, and are able to build multiple models out of as few molds as possible. What this means is that it is very rare for women's boots to truly be women's boots. Can they mold them out of pretty colors? Yes! Can they afford to make lasts that are specific to how women's feet are shaped? Not so much. For example many companies build all of the smallest size boots like 22, 23, and 24 in a women's specific last whether it is a mans model or a women's model. The 25 is usually a combo last that is a blend between mens and women's specific. And the 26, 27, 28, 29, and 30 are all mens specific lasts. Aside from color, some of the women's specific boots will have cuffs that are specific to the women's models that may be shorter, more flared at the calf, or have some sort of quick adjust spoiler shape that better accommodates a women's lower calf muscle.
Secondly deciding over the internet that your daughter is an 11+ in size is a nice number to know, but until she is properly measured on a brannock you are guessing. Americans do not ever wear their measured shoe size!!! How could we ever expect them to be comfy in their measured ski boot size? Her size, if she really is a women's 11 is actually a mens 10. Mondo point length does not differentiate between mens and women's. A 26 is a 26 regardless of the sex of the individual standing on the sizer. Which could mean that she is between the 26 and the 27 shell. And when the foot is long and narrow, it will call for the lowest of volume boot in the forefoot as well as over the instep and around the ankle to get a good fit. That means more than likely going with the smaller shell size to get the lowest roof, narrowest heel, and narrowest forefoot. if they are a little short at the big toe, you can always bump it out enough to give toe freedom. That said you should know that those dimensions are unicorn feet to the ski boot business. There is not a model or brand siting in a box that will be a slam dunk for your daughter. More than likely depending on her athleticism and skill you may be able to get her into a race boot from Lange, Atomic, or Dalbello. They all make a 92mm forefoot, softer flexing model that can flex down to approx 110/120, with a normal height cuff in sizes 26 and 27.
You could also go with the larger shell size and back fill the extra volume with a foam injected liner. However if you start with a shell that is too big and attempt to take up too much volume with injected foam, you run the risk of another bad boot experience. The shell shape and its proximity of match to the foot is the horsepower that delivers long term performance and fit comfort to the skier.
Another issue at this time is the amount of product or lack of product in the retail pipeline at this time of the season. I am not saying it cant be done, it's just that there will not be unlimited quantities of the type of boot that will work for your daughter.
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