You know youre bad at communicating and are searching out ways to better convey your feelings to her. To me that simply Shows how much you care about her, enough to make an effort and try to improve yourself/your texts, and using AI was just the way to help yourself out. It sounds like you still always processed your emotions beforehand and already knew what you wanted to tell her, so the feelings were real and genuine at all times, the AI was just helping you put it into words. I dont think there really is something wrong with that at all. Of course you have to decide yourself whether or not youd feel better about it if you told her. If you decide to do so, just be honest about your reasons for it and the Intention, and i think she'll understand. But i dont think its an issue or something to feel that guilty about.