My youngest daughter broke a bone her foot when she was three. I felt horrible because the first few days I thought she was ok too until her foot swelled up. (She had jumped off a picnic bench and landed just right that it snapped a bone). So we did the ex-rays etc. She was actually too small for a boot. So the doc had us keep heavy leather shoes on her for almost two months. She had to keep them on at all times (unless she was sleeping) to stabilize it (pretty much what the boot would have done). At one point, we even had to duct tape the darn shoe to her foot so she wouldn't take it off. For a long time after, her foot was sensitive and would hurt her if we walked too much (we pretty much walk, rarely use our van) so we would let her walk as long as she could and then she would ride in the wagon. She's over it now and hasn't mentioned her foot in about a year (she's 4 1/2 now).
My 5 yo son (7 now), however, also broke his foot that summer (the opposite one, completely unrelated incident) and he did have a boot. He was really unhappy about it. It throws off their balance and as the body compensates, it puts a lot of pressure on the hip, etc. So if they do give you a boot, expect your daughter to be very uncomfortable. They're simple to use though.
I was in a boot for almost two months this winter, so I know exactly why he complained so much now! LOL Big hugs. It will be ok. No matter how careful we mommas are, stupid stuff happens and we don't always realize how bad it is. For instance, my 6 yo daughter just sliced her finger open last week and had to have stitches. (She was pig headed and was trying to show me that she could too use my knives, even though she knew better; she's certainly learned the hard way otherwise.) I had no idea it was as bad as it was. I was concerned it took over an hour to stop the bleeding but I just thought it was a bad cut. However, I went to the dollar store to buy more bandaids, and her finger started bleeding again. An EMT friend happened to be there, saw the finger, asked when it had happened and said to take her to the doc. Otherwise, I probably would have waffled over it. I'm glad now I took her.
It will take some adjustments, but she'll be fine. :)