I have to admit, it had me stumped for a good ten minutes or more before I got the old brain-box in gear. Part of that time was spent in making sure he was telling the riddle correctly, so that it could be solved.
In true Encyclopedia Brown style, I managed to solve it before the end of dinner with the help of a few Cheerios.
See if you can solve this riddle (it may be easier to see it than hear it like I did ... then again, maybe hearing it is better):
The one before first is first of you;
the next of you is double of you;
the last of you is the first of you.