How do I know that this isn't, for me, just a phase? I've felt like a boy most of my life, but I never really learned about what being transgender was until about a year ago. I feel that my parents wouldn't take it very well, or at least my mom wouldn't. I asked her hypothetically a little while ago "What if I wanted to be a boy?" and she just shook her head no. Coming out or just telling her anything scares me. Any advice on coming out would be appreciated.
If you have felt like a boy most of your life, then it is pretty unlikely that this is a phase. You can always keep an eye on your feeling as see if they evolve over time. Sometimes, as you become more comfortable with yourself, your feelings can change a bit. I became more comfortable with my femininity over time. As for coming out, I would wait until you are in a situation where you are able to support yourself, since it sounds like your parents would not be accepting of you transitioning.