Really I should of known better... So some people know that I had recently wrote a letter about how I felt, that I might be transgendered; well, you can imagine, from the title, how that went. My grandmother was the one to read the note, and so far has asked every question that came before: Why? When? Am I gay? Why? The only difference is that she doesn't seem accepting at all; she's at least kind enough not to let anyone else in on it (per request actually, since no one else really needs to know), but I feel like I've hit the immovable wall here. She seems to be convinced that it's a phase, so I have two options: be persistent but subtle or finish college and convince her that I still feel this way (and by then, I will most likely be able to start supporting myself in case anything happens). I just feel sad and annoyed at this, but I suppose it's best to ask anyone if they have advice. Any support, besides advice, would be nice too.
Your work there is finished. You were honest with her and told her about yourself. It is up to her when she will decide to start taking what you told her seriously; some people never will, so don't worry yourself about it. If she thinks it is "just a phase" for now, it isn't your job to convince her otherwise, or to worry about it. She will realize that it wasn't just a phase eventually, and probably appreciate that you were honest with her all the time.