Are you doing the BB F! dining package or just a regular reservation?
If you're doing the BB F! dining package, then you'll be charged the adult price for your daughter regardless of what is ordered. Package pricing is based on age, so at 11 she would be considered a "Disney Adult" and charged accordingly. When ordering off the menu, the BB seems to be one of those hit-or-miss places. The most common answer I've seen is that they will allow adults to order off the children's menu, but a price comparable to an adult entree (e.g., double the price of the kid's meal). Ultimately, I think it's one of those things that you won't know until you're actually seated and speaking with your server.