Hair loss and hormone changes

I hope you can help me with this problem.  Over the last few months I
have begun to notice more and more of my hair falling out in the shower
and when dry.  Around 5 - 10 will come out in the shower and another 10
throughout the day.  I don't brush my hair often, and although it is
regularly colored, I do my best to keep it in tip-top shape.

Since I am fifteen years old, is it possible that there is still time for a
hormonal change to be changing the texture/fullness of my hair?  I
always thought "hormonal surges" were only for infants, pubescents and
pregant women!  But now that I think about it, my body will only be fully
matured in another three-five years!  Does this mean I can still possibly
have a hair change in store for me?

Also, another question:  As an adolescent, I naturally have very oily hair. 
In fact, most conditioners weigh my hair down so I am stuck to using
leave-in conditioners only.  But does having oily hair necessarily mean it's
more healthy and can survive more color treatments/perming?  Because
as much as I love my hair, I love my beautiful shade of rich auburn that I
can only maintain by dyeing my entire hair every month or so...  it fades
incredibly fast.

Sorry for the extra-long post.  But there's so much to ask and nowhere to
start!

What is your nutritional intake like?  Stress and poor nutrition are strong causes of hair loss.  Do you take mutil-vitamin, get plenty of sleep, enough calcium, etc?