I was in a similiar predicament when I returned to training after a 11 year gap. It bothered me at first, but over time it became insignificant and it dawned on me just how much I had forgot in my time out and that I didn't deserve to wear my previous grade in a dojo anyway. I had to start again but I am now back up to 2nd kyu. I suppose what I'm trying to say is that it doesn't matter what colour belt is round your waist, as long as you are enjoying yourself and learning new stuff. Theres no real rush to get to your dan grade and as someone has mentioned previously, the longer you stay at a certain level, the better you will become at that level.
