How could art contribute towards having a successful job and life?

Dear Julie, in addition to David's and Vivian's very grounded and valid advice, I would like add my two cents, based on personal experience. I have a deeply-rooted belief that arts in any form, painting, music, cooking, writing, designing, etc, are not only a medium for us to express our creativity and create amazing things, but also a medium for us to communicate with our community, building stronger ties with it, celebrating its unique culture, enhancing it. And by community I mean any group of people to which you choose to belong: your family, your neighborhood, your artist friends, your school, your church.
Yes you can have a very rewarding and successful career in the arts, as an artist, as an educator, as an administrator, as a communicator. Whichever of these sides of the arts you choose to pursue, the most important role you'll play will be that of a contributor to a society thirsty for the passion, empathy, and sensibility the arts can bring.
Continue to ask many questions, continue to connect with the artistic community closest to you, continue to explore and cultivate your creativity and talents. The fact that you are so passionate about your art is already a great first step in the pursuit of a career in this wonderful field in which we find ourselves.
Best of luck putting together your portfolio and applying to art schools.

Hi Julie,
You are definitely not the only one that thinks like that. I've heard, "Art won't make you money," my whole life. I had to keep reminding myself, art isn't about making money, it's about expressing myself and my passion. In the world we live in now, the only true thing is creativity. With the world everchanging and robotic taking over mindless tasks, expressing yourself through arts is an amazing thing, no robots/machine that do that. Let me tell you, months before graduating from college, my friends and family still doubted my success in design, but persistent is key. Remember that you aren't the only one and know that I'll be cheering for you on this end.
Good luck, Vivian

If you truly feel that art is more than just a hobby for you, I am sure you will find a way to make it an important part of your life. It wouldn't hurt to examine the possibility of attending Art School. Art school can give you the opportunity to work on your art 24/7 in an environment that provides instruction and promotes exploration of your specific interests without many of the distractions of high school. Once you have mastered your art, or, as you master your art (for this is a lifetime task) you can turn to the problem of making a living out of your art. Many of your questions, even those you haven't asked yet about art and its place in your life and how to make a living from your art will be be answered in art school where you will be in a community of artists, students and teachers alike, on a journey of exploration and discovery. If you pay attention to the journey and work hard you will discover how to make art a part of your life and the goal of making a living will be revealed.

My daughter faced just this question several years ago coming out of High School and has recently graduated with a Bachelor in Fine Arts and is attending Tufts for a Master in Fine Arts. Though making a living by making art is necessarily an easy path in life, musems, galleries and other places which collect art are opportunities to use your love of art in sharing with others. Digital art as the new media is often an area to express artistic talents but for the purist there are ways to make a career if, like everything in life you work hard.