It really sounds like it's fine. It should continue growing in the spring and not die back. Yes, it's growth from last season will contribute to the size needed to fruit.

If you REALLY want the main stem to friut,(and I'm assuming so) I'd cut off at least one pup. They take energy from the main stem, energy it could be using to grow to fruiting size.
Perhaps others who also bring their trees in for the winter will have more/other advise.
Good luck!
Mine fruited this past summer and we STILL have banana bread in the freezer..... Yummy
Barb

I hate to bust your bubble, but from my experience in Muncie with my bananas, it usually takes about three years to fruit one. I think it's because the bananas don't seem to count the winters, just the summers around here as time accumulated.So three summers=18 months. But as long as you keep that stalk growing, it's going to have fruit eventually. If that particular large stalk dies back to the ground, that restarts your time.
You can also plant it out in the ground in the spring, and dig it and repot it in the fall, or dig it and store it in a heated garage or basement for the winter.
I have an e-bay guide to banana care, attaching link.
You should also try the basjoo banana, you won't have to dig it at all or bring it in.
I also have another guide on indoor banana growing.

Here is a link that might be useful: how to grow bananas successfully in cold areas