First month BBTing, need help deciphering

On average my cycles have been 25-26 days. The original estimated ovulation day was CD15. This is my first month charting bbt and I was trying out the clearblue advanced opk first thing in the morning along with it. Well Glow ended up changing my predicted date to later in the month CD 17 and I ran out of tests before getting a postive.

Help! What day do you think I actually ovulated?

::UPDATE::

Downloaded Fertility Friend and inputed data. Attached the chart below.