Make friends at school. Participate in clubs, sports. Be a straight A student. Show great interest in healthy non-JW activities. This can be both, your cover and your way out. JW's will be disappointed at you, but not enough to shun you. Also, these tactics will prepare you for the next stage of your life when you are out of the JW control. And lastly, it will be a lot more fun. Besides, not all JW's discourage secular learning. My own JW brother has pushed his own children to pursue higher education so they can be self sufficient as adults.
Be a bit rebellious, be a spiritually weak JW, but a great human. JW's are not that stupid. They just feel forced to go along with the leadership and feel obligated to repeat the religious dogma spewed at conventions and kingdom halls..