IS THIS A POSITIVE OPK TEST?

Br

Today is supposed to be my ovulation day and I’ve been taking several opk tests but this is the first time it’s gotten really dark like this within 3 mins. So is this a positive opk test? And if so will how long does the fertile window stay open? First time using these and tracking my fertile days and ovulation days. I’ve never used these before and pretty bad I’m 30 too lol thanks ☺️