In response to the original posters original question.
To say I didn't originally start Aikido when I was 18 so I could get a "black belt" would be a lie. However, the group that I started training with changed my mind considerably by the examples I saw with them. The sensei of our dojo (George Reynolds) had studied for 10 years and was a 1st kyu when I first started. I recall the first seminar I went with him too up in Nashville, TN back in 1998. It was a Doc Jones Sensei/Dennis Hooker Sensei (From Shindai Dojo in Orlando, FL ASU organization) joint seminar, my very first seminar ever, and I had only been training for 6 months previously. My Sensei's Sensei (Dennis Hooker, Sensei) as I recall it from 9 years ago basically told my Sensei he was going to test for Shodan. My sensei really didn't' want too but he did after being told he was going to. It was seeing my sensei's non-importance placed on rank, and more so his being able to grasp the principles of Aikido that changed my mind significantly about attaining of rank. I trained for years and never tested, it just wasn't important. What was more important was my grasping the principles being taught to me by my sensei.
Now 10 years into my training I tested for my 4th kyu, and this time I had the reverse happen to me. I was asked if I wished to test and I said yes. After approximately 2 weeks more of training it was announced that I would test the next time we trained. Did I want too, nooooo, I didnt' feel ready by any means, talk about pressure. However, my sensei (Jim Novak) must have seen something in me that said test him next meeting.
Our instructors are always "testing" us. He tests us when we are working with others he or she tests us when we are uke for them during class, etc. We are constantly being tested. I believe during Seminars for ASU any 1st Kyu who wishes to test for Dan rank must attend 2 seminars with either Ikeda, Shihan or Saotome Shihan before they can test at which point the Shihan will evaluate he candidate for testing. Now there may be other rules that I'm just not aware of and thats alright. However, It sounds like to me that the Sensei is testing the candidate on their understanding of the "principles" of the techniques being studied. These are the same Sensei that will be testing the candidate for Shodan, etc.
As for colored belts and Hakama. One thing I love about my dojo is that anyone may wear Hakama from day one or not at all. Its up to you. Belts....i LOVE my dirty gross white belt. Its very special to me, and I woudln't trade it for anything in the world. It makes me understand why it took my sensei just about a year to change his old white belt into a black belt even after he attained Shodan. As I recall it, he was given one by another Sensei and told to wear it.
But that is why I love my Sensei, for he has completely changed my mind and allowed me to focus on learning principle not matching my belt to my Hakama color.
Now I wish to go higher in rank so that I may one day open up my own dojo, but I am glad that I learned some of those lessons above first.