Now is the absolute best time for you to start your business and get your feet wet in this industry. Now you probably have very little payments to make (probably a phone, and maybe gas for a car) so you have a lot of room to grow your business with the money you make from it. And you have the choice to keep it as small or as large as you want. Staying part time to get education is an excellent idea.
I graduated high school about a year and a half ago and went to college and hated my course. So I kept going in this industry and I'm in college for landscape design now to further my knowledge. People appreciate your hard work and plentiful knowledge on the green industry after going to school.
So work hard and do what you love, you seem to have an honest hearted work ethic, and people will appreciate that! One more thing, Lawnsite is full of stupid people, but there are alot more people who are helpful, so ask questions and don't let people get you down. We're all here to learn, check out some succcesful companies like Earth Turf and Wood, and Pro-Turf, and learn from them. You'll get an idea pretty quick of what works and what doesn't.
The owners of those succesful, larger companies all agree on one thing: You never stop learning in this industry. Whether it be from your own mistakes or from others!