That's a super dwarf cavendish. They'll always stay rather tiny in size and for fruit, are pretty picky with temps and take a long time. I find those even way up here in the Pacific Northwest sold as general houseplants. You can remove the pups whenever you feel they're big enough to safely remove without accidentally killing them. I usually wait til they are at least 2 feet tall, leaves included. By then they have their own roots, and aren't just a growth on the side of the mother plant. But yours being an SDC, I'd remove them pretty much once leaf #4 is developed.