Going without health insurance in the U.S. is colossally stupid. Doesn't matter how healthy you are, some major health issue can still crop up. Young, healthy people get cancer and other major maladies all the time.
A former co-worker of mine, a very healthy man in his early 30s, was diagnosed with bone cancer in one of his legs. He went through surgery, chemo, radiation, and PT over the course of about 2 years. After all of that, he has been in remission for years and is going about his normal life, but if he hadn't had health insurance, he and his family would have been bankrupted (and he probably would have died because he would not have gotten all that care if he was uninsured).
My otherwise very healthy son had appendicitis when he was 19. If we hadn't had insurance, the routine laparoscopic surgery would have cost over 20 grand.
If you think you might qualify for Medicaid, go ahead and sign up. Don't wait until you are sick - it's too late then.