Headaches in teenagers have similar causes as those in adults. Recurrent headaches, especially when coupled with other symptoms such as nose bleeds and changes in attention should be evaluated by a physician. Since her symptoms do not fit into one particular category, she should probably be evaluated first by a primary care physician
such as a pediatrician
or family doctor
Headaches and nose bleeds are two common problems that only rarely are related. The most common types of headaches are migraines, tension headaches, and cluster headaches. Migraines are usually on one side of the head, throbbing, and can be associated with the sensation of flashing lights. Tension headaches are both sides of the head and start in the neck and move forward. Cluster headaches are a little more unusual, and are associated with a runny nose, but not a blood nose. Bloody noses have many causes including dry air, irritating substances such as cocaine, and blood clotting disorders. Since your daughter's headaches may be associated with a change in her mental function (attention loss), then a rare brain tumor is always possible.
I suggest that you schedule an appointment with your daughter's primary care physician. He or she can take a more detailed history of her headaches, nose bleeds, changes in mental function, and perform a thorough physical exam. Perhaps given the combination of these problems, her doctor may recommend a head imaging study such as a CT scan or MRI.