There are important areas of the directory, that I won't name lest they suddenly get spammed, where the average wait is a day meaning they are cleared of all submissions daily. I regularly edit in categories myself with no waiting submissions at all. Others I edit in have sites that may be a year or two into their wait yet a new one submitted tomorrow might be the first one I list tomorrow. It might be that good and it might catch my eye. There are still more where I clear the category of waiting sites weekly but never list any - they are all misplaced and I send them all off to other places where they might get listed the next day if another editor chances across them, or again they could linger around for years.
Imagine if I get it denied, I would have to start the process all over again
Who knows. It depends why the site is denied. I haven't looked at it but it might be unlistable in which case there is no point in starting the process over. On the other hand it may be that you can resubmit and it hits the heap at just the moment an editor decides to clear it out - presto the site is listed in hours. It is so unpredictable that no amount of patterning based on averages, numbers waiting, named editors, or any other elements to be thrown into the pot will ever give you a usable equation.
Think positively. Classifieds sites require a lot of unique content to stand a chance. The longer you wait the more content you can accumulate, the better your chances. Reviewed tomorrow it might be rejected, who knows. Reviewed next month it might pass the test, who knows. One thing is for sure: the more content, the better you make the site, the more likely it is to be accepted when it is eventually reviewed.