Dear AM –
You are in a tough situation but don’t freak out. Clearly, your daughter is really confused about who she is. True transgender kids know that something is different with them when they are very young, the very fact that your daughter keeps changing her mind tells you that she’s experimenting.
Here’s what I would do:
First, rather than make this a gender identity issue, I would approach her and say that you are concerned that she is struggling with some deep feelings that she needs to figure out. Talk to her about your concerns about what is going on beneath the changes. Ask her questions and listen to her answers without lecturing to her. If she knows that you are empathetic, she will keep talking to you. She won’t talk about what is going on now because she knows that you want to change her mind (which is true, and I don’t blame you.)
Ask if she is struggling with depression, self-doubt. Ask about her relationships with kids at school. There are many kids who want to transition because they think it’s cool, to get attention, etc.
After you have established better communication, tell her that you support her but before she transitions, she needs to know a few things. She needs to be 100% sure that this is what she really wants and that being a man is what she believes deep down is true. Point out that the fact that she keeps changing her mind makes you concerned that she hasn’t arrived at that point. Also, tell her that once she transitions, she gives up her ability to have children. She will be infertile. Tell her that the transition will not be reversible and is she ready to be a man when she is 60? Tell her in a matter-of-fact manner.
Finally, encourage her to wait until she is at least 23 or 24 to make a decision. This is a very reasonable request since the medications and surgery are permanent and at 23-24, she will have the capacity to make a better lifelong decision. Ask her to pause and give herself time. Chances are excellent that this time will help her understand her true beliefs. Finally, remember to communicate to her that your love for her will never change regardless of the decisions she makes.
Lastly, find some women friends who can offer you support and keep you from exploding with anxiety. This is really tough stuff but as I have said before, never parent out of fear, but out of strength. You can do this.