I think some of the interim milestones might be skewed, but I think your overall goal is achievable. It's great to have goals, but a year is a long time to plan for, and you don't yet know how your body will respond to the diet. The danger is having these milestones in your head and getting stressed out trying to make them happen on schedule.
If you stay on protocol, I would expect you to hit the birthday goal no problem.
At that time, I'd set the next goal. Keep in mind that your weekly losses may slow down some... the holidays will come and go... life will happen. Or you may be so far ahead of the game, that you might want to set a higher goal. I'd shoot for the final result, but take smaller steps getting there. As you reach each milestone, set the next one... and make them achievable. That way you'll rack up success after success, rather than feeling you're behind plan from the get-go.
What you are undertaking is huge, and you are awesome for taking it on! So much of this is mental, and your resolve tells me that you're ready to dig in and get it done. It will be incredibly rewarding and empowering, but there will be rough spots in the road. So stay here on the boards and take counsel from those who can speak from experience... your peers will get you through. And if it happens that you need to deviate from your course a bit to get to the end result, so be it.
You WILL get there!