Any young disabled folks have Silver and Fit gym memberships?

I’m 30 and disabled, just got Medicare/social security. I have medigap coverage through i believe it’s the senior advantage plan.

I’m interested in silver and fit because, as I understand it, they allow you access to multiple participating gyms.

I called to enroll and was told I’m ineligible. I’m guessing I’m getting my flagged because I’m under 65. I have been receiving promotional material from Kaiser telling me I do qualify for silver and fit.

Wondering if anyone on here is under 65 and has successfully signed up for silver and fit. Thanks!