Ignore the bit about using sand, but this is generally a good general guide to growing your Aloe. Given that it's getting only morning sun, its pupping is probably delayed from not being in optimal conditions (full sun). If you can grow it outside in the summer, do so, and grow it as a tropical. Repotting will also help - is that Aloe potbound, because it looks like it could be so. If the plant's held up and the pot comes with it, it's ripe for repotting. Although A. vera is known to be able to be grown in many different types of medium, particularly crappy ones, it grows best in a porous mix.

Aloe Appendix

Aloes like a lot of light. Outside is ideal, or at least a south facing window is better than just morning light.

Yours look pot bound. My aloe vera grown in the ground has pups. The pups are basically coming from runners that comes out from the main plant.

With my Aloes, lots of light is the way for lots of pups. =)