How fortunate you are that your parents have the desire and means to help you achieve your dreams! Do not allow yourself to wallow in feelings of guilt - an “I’m not worthy” attitude is just an excuse to waste this opportunity. You “pay them back” by showing them that their emotional and monetary investment in you is worth it: study hard, do well, THANK THEM frequently, graduate and launch your career and life into adulthood. And then rinse and repeat with your children.