There are many many many jobs in the music industry. They will all require some musical proficiency on an instrument so you're starting out on the right track! There are jobs playing in orchestras, playing in churches, composing music on commissions for ensembles, marching bands, and other performing groups, playing at weddings, teaching private lessons, becoming a band director, teaching at the college level, as well as a variety of jobs dealing with music for children. There are jobs in music business, the recording industry, as well as music therapy for either children with special needs or the elderly. So many opportunities!
I'm actually reading a great book right now called, "The Savvy Musician" by Dr. David Cutler that talks about a variety of answers to your question. ((http://savvymusician.com/)
I'm switching from a Music Education degree to a Flute Performance degree and I was wondering the exact same question you are. This book is full of a lot of tips on how to make opportunities or take advantage of ones that are out there for music.
I encourage you to cultivate all of your interests in math and science, but if you want to get ahead in music, here are a few tips:
1) Start learning the piano. As a music major, I'm required to take a piano proficiency test. This includes scales, transposition (taking a melody from one key and being able to play it in another), sight reading, accompanying, and a few other basic skills. If you can afford to take lessons, that would be great, but if you can't it would give you such a head start to just teach yourself a few scales by looking them up on the internet.
2) Start to learn about Music Theory. Music Theory is the method to putting together pieces of music. Some REALLY helpful websites are www.teoria.com and www.musictheory.net No matter where you go to school, you will have to take a lot of music theory. For now, just practice learning what chords are, how to identify them, what intervals are, and make sure to use the ear trainers on www.musictheory.net As you learn music theory, if you have questions, your band director should be able to help you. You might even find that you really like theory and might consider a career in music composition!
3) Practice your flute! Even if you don't want to focus on flute in college, you will still be required to take lessons. I'm guessing, however, that since you practice all the time and love it, you'll want to take flute lessons. I would recommend the Dr. Clardy Flute Fundamentals books (her second just came out) to really make sure you are practicing the correct way. Your lessons teacher should also be correcting you. Nothing is worse than unlearning bad habits once you make them. Also, practice your Taffanel and Gauber exercises and start to explore the world of flute literature- learning, listening, and playing.
4) Join your high school choir. Even if you are not a good singer or care to be a good singer, you will be required to take Aural Skills in college. For this class, you'll need to be familiar with the solfege system. (do, re, mi, etc.) Also, you'll find your flute playing gets MUCH better because you are actually internalizing tone, pitch, and tuning.
5) If you have the time or the interest- or if your band program needs certain instruments- I encourage you to learn more than one instrument. Already learned piccolo? Try the alto and bass flute. You can start a flute choir at your high school or put one together to take to UIL events in your state. If your school's drumline needs an extra person on marimba for the marching show, take the opportunity! I personally joined the drumline and played bass drum. It gave me time to practice "non marching band" flute and improve my rhythmic skills.
Good Luck in your endeavours!