Ovulation day in question...

I’ve heard that Glow isn’t the best for predicting ovulation. So, I went to a TON of different ones and most of them seem to say the 27th (which is what Glow said). I’ve been trying to track my bbt, but I’m CLEARLY doing it wrong because my temps are all over the place and I’m sure it’s a user error rather than something with my fertility.

I have regular 28 day cycles and AF is usually no more than 4 days and it started on the 13th. I was basing everything off Glow until I started hearing that the prediction could be off. 😕 is it safe to say that I’m on my TWW now? Or should I keep on with the BD until AF is supposed to show up? 🤷🏼‍♀️