If they are indoors and ACTIVELY growing (meaning warm enough), it is OK.

I agree they have to be actively growing. Sometimes when they are indoors they are alive but not putting out a steady amt of leaves. Make sure that they are, or you have a good chance of losing them to rot. In the spring when they are outside and actively growing is the best time. I always dust my corm with an antifungal powder or rooting hormone after separation as well. Be sure to take a piece of the mother corm with the baby one too.
I like to leave at least a couple pups on all my bananas -seems to help with flowering but not sure if that is an actual fact. Some of mine seemed to keep wanting to put out suckers as soon as I removed them instead of directing the energy to the mother plant etc. My super dwarf has never flowered for me anyhow, and I heard it doesn't flower as much as dwarf cavendish and some of the others I have, so maybe with that one it doesn't matter if you take off the suckers.