You have only until Dec 7 to enroll in an Advantage plan. I can’t address her age, but I absolutely recommend an Advantage plan.
You can go to www.medicare.gov and find the plans available for her location. All plans are under Medicare control, so they are not scams. I am on Humana and love it - everything is paid for, including medications.
Another family member is on Optum (through AARP) and it is just as good, and covers her extensive meds completely. On Humana, her meds would be $3000 or more per year.
Hope this helps a bit.
I should add that I pay no additional premium, and get $75 per quarter to spend in their online pharmacy. All my doctors and dentists are in network.