No. I truelly think it should be hinted at in the first 2 movies, and show alot of Teela longing to know about here mother, and all her questions go unanswered, eventually causing a rift between her and her father, choosing to keep secrets from his daughter about her own mother and past.
Then in the 3rd(if there is a 3rd), Teela should have everything revealed to her at once, in an incredibley emotional scene, and she forgives her father, and everything makes scence to her, just before the final, epic battle scene.
Then after all that, At the end of the movie, The Sorceress reveals that her time as the guardian of Greyskull is drawing to an end, And that Teela was ready to take her place, and that by showing bravery, and courage in the final battle, she proved that she was ready to assume her destiny. Even still, Teela would show her doubts.
That would be the last scene with Teela, and its all left up the viewers to decide if they think she becomes the sorceress or not. Just my thoughts... What do you all think?