About When Did I Ovulate?

Hello everyone! My name's Lydia, I'm 20 years old, and my fiancé and I have been trying for our first child since October 2016. My cycles are always 30-32 days long and my period last 6-7days. I started testing on CD9 this cycle instead of CD11. My tests were getting darker like normal AMD were the darkest on CD15&16 and then they have progressively gotten more and more light. Do you agree that I ovulated sometime between the morning of CD15 and evening of CD16? All comments and opinions are welcome! :) I've tested with FMU and mid-day after holding for at least 4 hours without drinking any fluids.