my 2nd bbt chart, trying to pinpoint ovulation

20th month TTC baby number 1, it's been and continues to be a lonnnnng road. trying out temping from now on to see if I've missed something as well as starting acupuncture this month too. what do you girls reckon, when did I ovulate? and should I mark my temp shift yet or not? ps you can't see it on the photo as it's cut it out but I had 3 positive days of opks on days 13, 14 and 15 ☺️