If Medicaid covers you in your state just stay with them don't change if you can help it because If you change to Medicare it probably won't cover you, you will have papers or your insurance card or somewhere you will have the dates you're covered from and to, you can get pre approved on your current insurance, but if you change then whichever insurance is valid is the one responsible Hun. I managed a healthcare providers office and also dealt with the insurance department closely. But this was a few years ago, so do verify my info if possible.