Hello roxie heart,
I would not be concerned about your daughter having high blood pressure because of nose bleeds. If you think about it, adults with blood pressures 200/100+ don't get nose bleeds!
I would be concerned about your daughter having a hereditary bleeding condition. Though hemophilia is much, much more common in boys, there are several other clotting disorders that affect the sexes equally.
However, the seasonal decrease of humidity in winter is most common explanation for your daughter's nose bleeds, especially if your house is particularly dry.
Watch out for your daughter feeling light-headed, nauseated, feeling like she's short of breath, or if looks paler than normal. These could be signs she is anemic, or, has too few red blood cells.
Certainly, if these continue to be heavy you should revisit the issue with her pediatrician. For your piece of mind, you may suggest that she refer you to a pediatric hematologist, a doctor that specializes in blood diseases.
To your (and your daughter's) health,
Neil MD