M.S.
Yes! My 6yo had the same. Dr. said because she doesn't have hair in her armpits or private area that it wasn't pre-pubcent (not sure if I spelled that right) anyway, it has since gone away, just like the Dr. said it probably would. Girls are getting boobs/entering puberty a lot earlier these days due to all the hormones in our food, you'll find out from your Dr. today I'm sure whether it is that she is entering puberty early or just something to keep an eye on for now.
M.