On that chart, the average woman would ovulate at about Day 14, but remember that you are not necessarily average. Watch for signs
of ovulation, such as eggwhite cervical mucus
. Mark these on your chart. Then when you have three or four months of information (start a new line at Day 1 when each next cycle begins), you might be able to glean a pattern from signs and signals (such as mucus changes, aches in the ovary, etc.) that tells you when you ovulate.