I'm with Jeff- it's hard enough to break even with a reasonable business plan. Rescuing burms is simply a more fun way to lose money than burning it or flushing it done the toilet. Just as certain, however, in my opinion. 'Rescuing' *any* animal(s) is not a money-making venture. Every rescue, shelter, etc. that I know of depends upon the largesse of the owner, or donations from the public. Most of the successful ones are non-profit or charitable groups, and while they do have some income, it is usually a struggle just to survive, never mind repay loans and make money.
My advice- don't get a significant loan when you're 18. Perhaps a small one to start a summer business to operate while you're in school getting an education. Business experience is never a bad thing, even if you lose a bit of money here and there. Just don't sink yourself into a major blunder with a 37 year (who gives loans like this anyway) repayment schedule without trying some small steps first!