How do you count garter ridge?
Point your needle-tip to the right. Count the garter-stitch ridges, not counting the cast-on row. Each ridge counts for two rows. If you count 12 ridges, you have knitted 24 rows.
Does the cast on row count as Row 1?
The cast on itself is not counted, however, some cast on methods create both a cast on and a knitted row. For example, the most popular cast on, the long tail method, creates both a cast on and a knitted row. So in this case, you would count that as the first row.