VBA Code To Shade Rows With Like Values

I am fairly new to VBA and I am having some trouble with a VBA routine that was used in some workbooks I was given and I am trying to reuse that code.

What I am attempting to do is to shade the rows (alternate colors) whose value in Column C is the same until that value changes.

Example:
Row 1, 2 & 3 all have the same value in Column C so these would shade color 15
Row 4 thru 10 have a different value in Column C so those would have no shade
Row 11 thu 13 have a different value in Column C so these would then be Shade 15

So here is what I have done:

I set the range for the routine to step thru, then I defined the row & column to start processing. I then compare the current row to the row above. If the values are different then I compared the colors of the rows, and set the active row to the opposite color.

This routine runs but the first cell in each grouping isn't being shaded but then the rest of the rows are shaded correctly.
I have searched the web and look thru my code several times but to no avail, I cannot seem to understand why this will not work.

Code:
Sub grid_coloring()
Dim rwIndex, colindex, colindex2, ncount, bcount As Integer 'set rwindex, colIndex as an output number for columns. bcount and ncount are for counting blanks and dupes
Dim theRng As Range
Dim FirstRow, FirstCol, LastRow, LastCol As Integer

[Code] ..........