You are not an idiot but your mom's right that you need health insurance. But, good news; there are 6 month policies one can get that don't cover a lot but they do make sure if some catastrophe happens you are covered. Go to eHealthInsurance:

http://www.ehealthinsurance.com

and look at the "short term" plans. They're expensive but maybe your mother will pay? My father got me one from Mutual of Omaha when I was out of college but before I'd found a job, etc.