Hi Amy,
I don't think you have anything to worry about at all. Basically, out of every 100 kids her age, she is taller than 30 of each 100 of them, and is exactly perfect at 50%, being exactly in the middle, not the smallest or the biggest. Honestly, I think the height and weight scale needs to be updated, becauase I think there are much bigger kids these days.
All 3 of my girls seem to be getting bigger as I have them. My oldest daughter turned 5 in July, and only weighed 34 lbs, and was 40" tall. She fell in at 10% in height, and 5% in weight. (I also worry about her weight, only I'm trying my darnedest to put some padding on her little body instead. No matter what I do, though, she will only eat unil she's full and I don't force her to eat more, except maybe "3 more bites". The doc has reccomended that I try to get her to gain weight, but I can only force so much upon her.) My 2.5 year old weighed about 32 lbs abd was about 36.5" tall at her 2 yr checkup. She was border line heavy, but because of her height, doc says she's fine (she's 95% in height and 90% in weight). Seven months later, she is almost as tall as her 5 yr old sister, and wears the same shoe size...9. My 13 month old weighed 20 lbs and was 31.5" tall at her 1 yr checkup. She's even taller than her 2 year old sister was at her age (97% in height) but is skinny like her oldest sister (50% in weight). Overall, all kids grow differently. I was and have always been "thick". I can lose weight, be in good shape and weigh as much as my shorter (older) sister, but I still look a lot bigger because of my frame. I imagine my 2 yr old will be like me, but much-much taller than me (I'm 5' 4"). Their dad is the skinny tall one (6' 3") and he's the "runt" of his family of brother, dad, and uncles. I imagine my oldest and youngest will be bean poles just like him.
As long as you feed your daughter healthy foods, and she's not just sitting around watching TV, I think she'll be fine. In fact, it sounds like she's perfect. :o)
Mari