I'm in the same boat bro, I realised two and a half years ago that I was trans and decided 1.5-2 years ago that transitioning was definitely for me. But I won't be able to start until I graduate high school this year, and I've been waiting so long that it's getting hard. I just keep telling myself I've only got a little less than 8 months left. And that number is coming down quicker than I expected, I feel like just yesterday it was 10.
I've found that planning things out, for example, the day I want to come out on facebook, the day I want to schedule my first T shot/patch/whatever I end up with, etc. really helps me focus less on the now and more on the future.