>should I re-submit my site under the correct category with a short note explaining my error?
First of all, a perspective. Most suggestions are imperfect in some way (or ways): wrong category, inappropriate descriptions, even the wrong URL. All these can be fixed. If a suggestion points to a useful site, it's a helpful suggestion, even if it's not as helpful as it theoretically could have been.
So, in your case, a resuggestion is not required. (How can it be, you're a volunteer?). But it might make the original suggestion more helpful. And the note of explanation would also be helpful.
So long as you're helping, nobody will complain.
