How to create my own software/program/online thing?

For years I have searched for an easy, simple way to organize my to-do list. School, random stuff, etc., everything I've tried just doesn't seem to work well for me. So just now, I thought, why can't I make my own? Mold it around my needs, and maybe even share it with others? I want to create a program, or software, or whatever, maybe something like an iPhone app, but of course I'll start with something on the computer. How does one go about something like this? Does it take years of experience or can I just watch a couple video tutorials on youtube and get started? Just need something to point me in the right direction. Any help is appreciated, thanks!

First you need to learn the programming language required for whatever operating system you use. Normally on a computer that would be C or a derivative. That will take about 6 months hard work if you are capable of thinking for yourself, but will leave you no time to organise anything during that time. You then write the program and compile it. Then debug it. You then re-write it to fix whatever errors it contains. Then compile it again and continue debugging until it no longer has errors.