IF you are using a college fund to pursue a diving lifestyle you need to seriously sit down and rethink your priorities. The facts of life are that SCUBA is a hobby. If you want to go into the teaching area of the hobby, don't expect to make any real money.
There are very, very few people who can make a good living only from the dive industry. It takes money to make money. Want to own a shop, and be the boss (the only way to come close to making money) you better have a LOT of money starting out. You asked one poster to elaborate on that thought so here goes.
You will need money for shop space rental
You will need money to purchase the "rights" to sell scuba gear. Every brand has there own minimum starting order, often $50,000 or more per brand.
You will need money for advertising
You will need money for air compressor and nitrox blending equipment
You will need money to get yourself trained to instruct
You will need money to purchase your rental fleet of BCs, regs, tanks, computers
You will need money for someone to run the shop while you are out teaching
You will need enough money to live for one year with making money at the shop.
And lastly, you will need to convince enough people to buy your training and gear to pay the bills.
Quarter Million to get through your first year probably wouldn't be too much.