@John Moorhouse - There are many reasons you want to stay in school and at a minimum get your High School Diploma.
1. There may be the opportunity to work on non-tradition subjects that can help you in real estate. Subjects like accounting, writing, technology/web design, public speaking, and financial literacy will be critical for success.
2. Real estate success does not happen in a vacuum. To be successful, you will need to work with others such as contractors, government officials, tenants, mentors, bankers and investor partners. To work with people like this, you need credibility. Dropping out of High School (regardless of reason) will be a black mark against your credibility and it will be that much harder to convince these partners to work with you to grow your real estate portfolio.
3. Be patient. The housing market is very hot now and there is a good chance that the market will soften soon. By the time you graduate, there is a good chance there will be more good deals out there. Plus you will have two more years to scrimp and save and build your capital base and you will be better prepared to act when the market softens.
Good luck.