If the rental period is less than one year (or maybe it is one year or less), the "vacation home" rules apply which require the days. In that example, the rental period is less than 1 year, so yes, you need to count all personal days during the year.
You are used to the situation where it was personal use then converted to 100% rental use for over a year, in which case you would be right, the personal days before it was converted to a rental don't count.
