wooÐs,
You're still thinking of "quitting" as part of your future.
Make it part of your past.
If you absolutely can't do it today, that's okay. But you've got to set a date and time and stick to it. And it won't mean a thing if it's more than a week away - that will just give you more time to postpone it.
ps - tell your Mom about it when you do it. That little bit of extra motivation might just put you over the top. Ask her to keep her questions and comments to herself, though - tell her you'll give her progress reports. Just think how good it will feel to call her up and say, "Not a single cigarette in 10 days."
Which, BTW, you could be saying today if you had quit when you started this thread