I came out to my mom, and she said I'm probably just a 'tomboy'?

So I came out to my mom. I told her that I thought that I was transgendered, but I don't know where I am on the 'gender spectrum'

She said that she had no idea what to say, or what to think. But after a little bit of explaining myself, she started saying that I am probably just a 'tomboy' and that I am a mix of both male and female hormones (just like everyone else) And that I am a girl, but I don't have to be a 'girly-girl'

I'm fucking pissed off now. When she said that, I finally came to my senses. I AM transgender, and I AM FtM.

So I'm going to ask all of you transguys on here, or even transwomen:

How did your parents react, how supportive were they? If they were like my mother, how did you convince them otherwise?

Thanks for the responses