Hi S.! I, too, thought that when a child is really tounge tied, that they clip it pretty early on. I wasn't technically tounge tied, but that 'connective thingy' below my tounge was closer than what I thought should be normal. I felt that it interfered with my speech some, and I definately couldn't stick my tounge out much beyond my lips. When I was 18 or so, I had mine clipped at the same time that I had my wisdom teeth pulled, and I'm so glad that I did! It feels so much better, and I can actually stick my tounge out, which is great now that I'm married (haha - kidding ;0)
Not sure that that helps you at all, but I would consider having another Dr. take a look to see if this is something that should be done early. I was told that if my speech had been affected by the tied thingy, that it would take speech therapy to fix it, after I had it clipped...so why wait for your daughter to actually have speech problems?
Blessings,
Renee