I misread one piece...you're on the deed and mortgage, but you don't occupy the house, it is a house just for her and you're paying the entire monthly note? Good deal for her...that may be a gift event...however, I still think the fact that you have a debt obligation and ownership may eliminate the gift tax implications. She can't sell the house on her own and walk away with the proceeds...it isn't 'just her house outright'
For a gift to be a gift, the recipient has to have unfettered control of the asset. In this case, she does not.
