PPPlan

I’ve found myself lacking a solid estimation capacity.
What I’ve found working is slicing any task into smaller tasks until I come across finite tasks I feel confident I can estimate; furthermore the need for estimation makes me reason and plan my steps to a manageable and clarifying level.
While I can, and am now, doing it using a simple txt file I’d like to write a small PHP application to help me along the way and speed up the process of tabbing here and there and “gamify” the estimating experience all the while.
For the first incarnation I’ve chosen to go with a command line interface to avoid wasting time in anything but trying to nail down the business logic behind it and get an idea of the working thing.
In a most basic incarnation the script would ask me questions and store my answers like

script - What do you want to do?
me - Create a plugin that does A and B.
script - How many hours will it take to create a plugin that does A and B?
(Either a fraction number or 0 for "I do not know")
me - 0
script - Ok, what's needed to create a plugin that does A and B?
(Answer with a comma separated list)
me - make the plugin do A, make the plugin do B
script - How many hours will it take to make the plugin do A?
(Either a fraction number or 0 for "I do not know")
me - 2
script - How many hours will it take to make the plugin do B?
(Either a fraction number or 0 for "I do not know")
me - 0
script - Ok, what's needed to make the plugin do B?
(Answer with a comma separated list)
me - set some setting, create some validation ui
script - How many hours will it take to set some setting?
(Either a fraction number or 0 for "I do not know")
me - 1
script - How many hours will it take to create some validation ui?
(Either a fraction number or 0 for "I do not know")
me - 1.5
script - Any more things to do (y/n)?
me - n
script - Here's a list of the things to do do "Create a plugin that does A and B":

    make the plugin do A (2 hrs)
    set some setting (1 hr)
    create some validation ui (1.5 hrs)

that's a total estimate of 4.5 hours.
Do you want to save the list to a file (y/n)?
me - y
script - the list has been saved in todo.txt.
Go work

This surreal dialogue should take place any time I find myself stuck and/or unable to estimate the work to do.
I’ve put up a GitHub repository to store my progress and have committed a dumb first iteration.

I appreciate your input