Your daughter probably doesn't have anything wrong, but my suggestion would be to check it out anyway. My son started having b.o. when he was 5. Because this seemed abnormal to me, I asked his pediatrician (who blew it off) and my former father-in-law who's a doctor (who merely suggested using deodorant soap....but I was addressing a medical concern and didn't need hygiene advice).
Later, when he was a teenager, it was clear that he had not been growing properly. FINALLY, I got another doctor to take it seriously and refer us to a pediatric endocrinologist. She diagnosed a hormonal disorder. At age 15, his growth plates were 99% closed, and it was too late for growth hormone to work. He was 5'2" at that point. The good news is that he's continued to grow, despite the dire prognosis, and is now 5'5" at age 19. This is still several inches shorter than what his genetics would predict him to be.
My point is, that you should consider pressing the point with more than one doctor until one will take it seriously and do some testing. At best, a disorder can be found early enough to prevent permanent problems. At worst, time and money may be wasted, but your mind will be set at ease with medical tests that reveal no problems.