Her nose keeps bleeding

This is the 3rd time she bleeds from her nose but it's never happened before! my daughter is 7 years old and sometime last week she told me she was Bleeding from her nose but I was driving so I could turn all the way but I did glance and saw just a bloody booger. This Friday that passed she spent the night at my mom's and was told she bleed a lot from her nose. Yesterday she bled much to were my mother in law suggested us to take her to he doctor cuz it was a lot!!! Also cuz some stringy type thing came out her nose which my mother in law said it was a vain. We were on our way but not even half way there she stopped Bleeding. Went back home and today she bled again but it was just a little. It is something to be alarmed of?