Wrong, Nirn and Anu created the universe, Lorkhan a daedra created the idea of making the mortal world of Nirn and the et'ada are the earth bones. The Aedra are just beings that decided to back out of being earth bones but not fully returning to Aetherius.
Actually, it was Anu and Padomay/Sithis.
Those two created all of the Aedra and Daedra. Where the Aedra are killable and the Daedra are not is because of Lorkhan.
He tricked the Aedra into putting too much of themselves into the creation of Mundus, and because of that they suffer from a limited form of mortality in that once they die, they cannot reform unless a particularly savvy Mortal can somehow Mantle themselves as the former God (ex. Talos).
The Daedra & their Princes were not tricked like this, therefore they simply go back to the Waters of Oblivion and reform at full power at a later date.
So yes, the Aedra are actually less powerful than the Daedric Princes. That's why there's no stories in the Lore about the Aedra marching into Daedric Realms and just whoopin' ass. The Daedric Princes are almost literally unstoppable while in their own Realms.