Congratulations on your initiative. Assuming, as you said we should, that you know next to nothing, I will say this:
WordPress is built such that no real working knowledge of any web coding language is required. But of course, that's severely limiting. That would be like buying a car without knowing how to drive, and paying a tow truck to tow you around town while you sit behind the wheel. You're getting where you need to go, but you're missing the experience. So again, I commend your initiative.
Luckily for you, there are a tremendous number of tutorials and lessons available to help you continue expanding your knowledge. If you would like my opinion, here are the disciplines required to run and maintain a wordpress site, and in the order of which you should learn them.
1. HTML (This is the markup language that controls the structure of elements and content on every website.)
2. CSS (This defines a set of rules that control how the elements on a website display.)
3a. WordPress Interface (Learning how to use the WordPress Dashboard, is essential. I recommend learning this after HTML and CSS because those languages will help you understand what you can achieve with the Dashboard at a conceptual rather than just visual level)
3b. WordPress PHP & Basic PHP - (This is the programming languages that WordPress is built upon. WordPress uses PHP to generate HTML dynamically and create pages, menus, etc. I say WordPress PHP, but what I really mean is the core set of PHP functions, classes, and snippets that every WordPress webmaster should be familiar with.)
Below, are some places to start learning what I laid out above. I hope you find success with them. It can be arduous at times, but it is at the same time, very rewarding.
1. HTML - Tuts+ released 30 days worth of free lessons to help you with the most basic of basic. http://learncss.tutsplus.com/
2. CSS - See above. That will show you all the basics. Once competed, you should know what you need to learn next (with regards to HTML and CSS) and know enough to find out where to learn it.
3. WordPress and WordPress PHP
Start here: http://codex.wordpress.org/Main_Page under "Learn How to Use WordPress". Then see below.
WordPress PHP - If you use a theme someone else wrote and then try to make changes, you're hacking it up. In all likelihood, you'll be making changes in a trial and error fashion until you achieve what you want to achieve. Learning WordPress PHP will help you fundamentally understand how ALL themes are built for WordPress. The easiest way to do this is to create your own basic WordPress theme to help understand the basics. You can start here: http://themeshaper.com/2009/06/22/wordpress-themes-templates-tutorial/
You'll also want to learn the following basic PHP and WordPress PHP. There's seemingly an infinite amount of information, but you can take a site built with HTML and CSS, apply the following, and you'll have a WordPress site. To me, this fact makes the following PHP required knowledge, and so I'll list what's most important for you:
The Loop: http://codex.wordpress.org/The_Loop
basic syntax: http://www.w3schools.com/php/php_syntax.asp
variables : http://www.w3schools.com/php/php_variables.asp
arrays : http://www.w3schools.com/php/php_arrays.asp
echo() : http://www.w3schools.com/php/func_string_echo.asp
If...else conditionals: http://www.w3schools.com/php/php_if_else.asp
For Loops : http://www.w3schools.com/php/php_looping_for.asp
While Loops : http://www.w3schools.com/php/php_looping.asp
Functions : http://www.w3schools.com/php/php_functions.asp
(After this, google for tutorials of projects you'd like to achieve, then make them your own. That's how I learned)
I spend everyday working with WordPress and I use the skills above every day. By their nature as the most basic, they are used most frequently, so it's important you understand and remember them well. Obviously certain things will extend beyond the scope of what's above, but it's as good a place as any to start.
I hope this helps, and good luck!