A 20k bank loan after interest is going to be like a 30 k loan. The maximum recommendation for loans for all four years is 27k. Can you afford $500 a month repayment when you are away in Israel and while you are going to school? You might not be able to afford school at all if you have to pay $500 a month for this loan.
If you think 20k is not a lot, then take a year off of school. Work and save 20k. Then go without any worries.