There are some ideas posted in my thread at
My Mystery Busy Bee Banana.
I have seven hands on this banana now and think I'm going to cut the bud off the flower in a day or two, remove some hands, and possibly even remove many fingers down to 50 or so, hoping these can then mature faster. You don't have that many fingers yet so that may not be necessary. You might also construct an inexpensive temporary shelter for it, even just something directly above your banana to prevent frost (i.e., no sides). Just 4 poles and some poly film on top might extend your season a few weeks.
Good luck!
Harvey