How can you calculate the odds? Simple....You can't
I'm in the same situation. I've been working in Korea for 4.5 years and will start training early next year. I will pay for all my training in cash and don't expect to make a decent amount of money for a number of years. I'm taking a chance by spending so much money, but it's a chance I'm willing to take in order to try and fulfill a lifelong dream.