There's a difference between dedicated and prepared, and obsessive-compulsive
I once read a letter in Aikido Today from someone who said they continually wanted to do a kyu test over and over because they felt they didn't get it right. In a sense that's arrogance, not humility, because it disregards the opinion of someone wiser than you (your sensei) who told you when you should test. In my experience, when you're told to test, you're already there. This doesn't detract from the seriousness or the "stage fright" some have of being "on" in front of an audience of your peers, superiors, et al., but harmony is also balance.
An illustration: when I was a teen-ager I played a lot of golf. I realized I could play every day in the summer, so I did. I got much worse. Why? Instead of playing and being in the game, I started to analyze my backswings, my breathing, etc., and broke everything into "parts" which also broke my game apart. You can do the same with aikido. Aikido techniques are like flowing water, not the segmented frames in a film strip.
Enjoy practice. There's enough seriousness in what you do off the mat, achieve in that world, "live" and be "alive" on the mat!