Hi!
Well, since there are different styles and organizations of Aikido, I think the best answers you'll get to your questions will be whatever the instructor tells you when you ask him (or her) in a few days.
Most Aikido dojos/systems (including mine) have only the white belt and the black belt. A person won't have a different belt color until they reach black (or accidentially wash their belt in a load of dark laundry or a red shirt or something). However, I have heard that there are some Aikido schools around that do use the color belt system. Nothing wrong with either way--just depends how the school is run.
Attaining rank for my mom and I was like this--after we'd been going to class for nearly a year, sensei told us that we were going to test for 5th kyu and he made sure that we knew (at a 5th kyu) level our list of techniques. (Each kyu has a short list of techniques that we are supposed to be able to perform as best as we can when we test.) We tested months later, passed, and got a certificate. Same thing a year later with 4th kyu. Then the head of our association passed away and no one has tested for anything the last couple of years. Doesn't matter to us though because we're still in class learning and sensei verbally promoted us to 3rd kyu awhile back (he would only do so if he thought we were at that level). So I imagine that for testing purposes, there will be a list of some techniques to perform, and many places test way more often than we do. Some schools even have tests for 8th, 7th, and 6th kyus.
One thing about Aikido that I've started to understand a few years back is that it's very complex! The more I do it, the more I realize that I don't know. The black belts in my class say the same thing. It's definitly not boring! I hope to be able to do Aikido for the rest of my life!

artyon:
If you want to read some interesting info on Aikido
http://www.aikidofaq.com/ is a good site.
Lots of luck and please come back with any other questions, opinions, and especially come and tell us about your first class!!!!
Robyn :asian: