Af "NOT" Due May 18th, Ovulation date?

Laura • Mother to 4: 1Baby: Amanda July 16, 2012 2Baby: Wyatt February 27, 2014 3Baby: Emma July 16, 2015 4Baby: Harley May 4th, 2018
Heyy everyone, 
So I've been using an OPK (Clearblue Advanced) this month and looks like the <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> is off by a week. I was to Ovulate on April 30rd, but I've got my first high on 5/2. Today I'm hoping to get a peak result (5/5). Plus my cycle has only been 28-30days long and I'm already cd 20. 
(This is a blinking test but can't post video or I would)