I doubt that you can change her mind after she has already bought the tickets and contracted the AB&B
Console yourself that traveling, as far as COVID-19 goes, is safer next week than last week.
Trump just eliminated a bunch more international travelers and lots of events that would have put a lot more people on planes have been cancelled.
You could also give her some advice that she wont take for after she gets to Florida like:
Dont go out to bars, dont eat at restaurants, stay at least 6 feet from any attractive young men she may meet (social distancing).
It is best if she stays in the house or walks alone on the beach.
I’ll be 63 in a couple of weeks, we’re taking a vacation to Jamaica. I think it’s all been over hyped. If I were 20’s, and had the time, I’d go everywhere while the tickets are cheap.