A lot can happen in three months: Thanksgiving, Christmas, New Year’s Eve, Groundhog Day. (I swear, that shadowy rodent needs his eyes checked.) Oh, and despite feeling like your late-50-ish self, you find out your heart’s mitral valve leaks excess blood and some lifelong Wolverine fan will fix it, but not right away, of course, more like the day after Memorial Day so it sinks in for a couple of months. Good times. But enough about that. I haven’t been to a Jazzercise class since last Veterans Day, and it shows. For those of you not well-versed in the art of sweat, Jazzercise combines dance with exercise, including cardio, free…