Medicare has not changed any, just "Medicaid" includes more people now. Medicare is Social Security-related so you have to qualify for Social Security or be 65 or over. So, if you are on SSDI you get Medicare, SSI or can't afford any other insurance, it's Medicaid.

At 65 everyone switches from whatever insurance they have to Medicare. I'll be 64 this year and though I get my Social Security check (since being 62) I won't be eligible/be forced to take Medicare until next year. Everyone gets a "basic" level of Medicare and then can add the different extra parts so more is covered if they have the money/want to. What is Medicare? | Medicare.gov

Because I'm retired but not yet old enough for Medicare, I had to buy my own insurance but was rejected because I am overweight. However, Maryland has always required health insurers in the State to offer other plans for people who got rejected, couldn't afford insurance, etc., so I have an MHIP plan (Maryland Health Insurance Plan) which is just a regular Blue Cross/Blue Shield PPO that I pay a whole lot more for than I would if I weren't overweight. Maryland's insurance marketplace website was just as bad as the Federal one so instead of having to buy a plan there and the MHIP being discontinued, they are just continuing MHIP until everything gets settled. My particular policy is just like what I had at work before, so I hope nothing changes until next year when I'll do the whole Medicare thing and have to figure out who to buy the extra parts from, etc. Fortunately my husband is older than I and has all that so I'll probably just get whatever he has.