It's completely fine to create accounts from Non-Played Characters, however making her mother yourself is sort of redundant, since if you were to have a thread with her, you would be threading with yourself, which defeats the purpose. If you really want her to be created, find someone who is willing to play her. Once you've done that, you'll need to get the okay from the administration to have that person adopt your character before you should start to collaborate with the other player about her sheet. That player will then need to create her character sheet and submit it before you can play.
I hope that helps!