I get that you had plans for the daughter you thought you had. You thought you had a little princess who would grow up to do great things. She doesn't exist though, no matter how much you push it. You have a son and you aren't going to stop him from being the best man he can be.
I'm surprised you didn't know from early on. Actually, you probably did from the comment you made in Walmart when I was in middle school. "You know you're not a boy, right?", you said. It hurt, and I didn't know why, because I didn't know anything about being transgender. I thought I was just a girl who felt like a boy.
Some more comments you've made much more recently still stings because I know I'm a boy now. I remember correcting you when you mis-gendered my friend and you said "That's sad. They should just stick with who they are." and then proceeded to tell me that you had watched a documentary where someone had regretted transitioning.
The worst thing you've ever said to me was last fall in a Target parking lot when I happily said that people were seeing me as a man now. You told me "No matter what you do, you'll always look like a girl." What you said is the reason I'm crying while writing this.
I can't understand why you won't accept you have a son. I haven't changed at all. I still laugh too loud when watching Let's Plays and I still sped a lot of my time playing Pokémon. The only part of me that had changed is my name and pronouns. I'm still your child.
I hope you finally see me as your son before its too late, because life is too short for your son to keep crying.