Is a 21 light of day cycle run of the mill?

I have my time of year usually every 17-21 days as apposed to a 28 day cycle. Is this majority?Is a 21 light of day cycle run of the mill?
The 28 day cycle comes from averaging hundreds of thousands of women's cycles, and to arrive at an average in that have to be society above and below the average. So to be less than 28 days isn't that strange.
its ok.
yes, its different for everyone.
That is Ok, the cycle vary from woman to woman.
yes. for about 5 years i would enjoy a cycle where the year that my period done you could count 20 days and then i would hold it again...
I guess nothing is wrong.I own never had a28 days cycle any where on earth between 14 and 35.