"If you believe you can do a thing, or believe you can't, either way, you are right." -- Henry Ford The nice thing about deadlines you set for yourself is that you can ignore them, or get the job done and not have them hanging over your head. Your choice, right either way, for you. (*hug*)
I stressed myself out over and over trying to tell my wife, and one day it just slipped out very naturally and clearly at a very opportune time.... I think you have to know in your heart that it's the right thing to do and you WANT to do it, and then either set a date (as you are doing), or just keep watching for the right time. The important thing is to recognize that it's what is best. If you go through with it today, I hope it goes well. Just know that whatever happens afterwards, even if there is pain or difficulty, you will have a huge weight off of you. Take care.
Awh, don't worry! I've lost count of how many times I've said I'd do it by a certain time and not been able to go through with it. It just means you need a bit more time.