I think iwasanurse probably answered your question and is probably correct. I would double check and call Social Security at 1-800-325-0778

I had private insurance and they covered me until I turned 66 and eligible for Medicare. I never even heard of a Medigap or if that is for people who do not qualify for a Part B supplement because of there age.

I am sorry if Medigap is your only option because you are younger.

Scrubbs