Your daughter is 8, so it wouldn't be so unusual.
As a side-note in addition to the other great responses, just want to add:
Nowadays, "puberty" starts at around 8 years old. If it starts before then, it's called "precocious puberty" in which there are MANY different 'kinds.' ie: breast buds, hair growth, menstruation etc.
For us, we saw a Pediatric Endocrinologist because our daughter had some "spotting." As a matter of procedure, the Doctor asked various questions, and my girl had to get the "bone age" x-ray of the hand etc. In any case, my daughter's "ailment" subsided... and it turned out to be a urinary infection. My daughter is only 6 years old. But as it turned out, her "bone age" is within "normal" range although a little more than her age.
In any case... I just wanted to relay some crucial information here, which we got from the Pediatric Endocrinologist... and that is: one of the questions he asked us/my daughter was "what kind of pictures do you have on your wall and what do you watch on tv?" (the reason is, he said MANY MANY children watch "teen" & "pre-teen" shows at such a young age AND they have the posters on their walls too and dress like that already. He says it is an environmental "influence" on a child's development). His point being, it negatively impacts a child's physical development even... and that it is simply inappropriate... and that Parent's need to think about that. And it "can" perhaps trigger or induce a child's physical development, adversely.
Also, staying away from 'hormone' filled foods... ie: soy milk, artificial growth hormones in dairy/milk, BPA's in plastics etc. ALSO, the Doctor said that in one case, there were 2 children under the age of 8, (a boy and girl siblings) that were getting behaviorally aggressive and getting abnormal hair growth already. After much investigation into their lifestyle... it was found that their Dad's "hair growth" cream for baldness, (which has testosterone in it), was causing their precocious puberty, abnormally. Just from normal physical contact with their Dad and skin-to-skin contact...the hormones was being absorbed into the children's endocrine system.
So, many things can "harm" a child's endocrine development. It is very complex... from the media they watch to what they ingest or touch, on a continuous basis.
Thankfully, my daughter was fine. But this is how we learned all about precocious puberty. They say that nowadays... "10" years old is the new "15" years old. This is how fast children are advancing... whether for good or bad.
All the best, just wanted to pass along some info.,
Susan