1st time OPK user. Is this a surge or should i keep testing??

A little background info on me, I had my son a year ago and got my period back 4 months ago so I'm still figuring out my cycles. The norm for me lately is a 31 day cycle and ovluation pain between CD17- CD19 (which I still haven't had this cycle). Is it possible that CD14 - CD16 was my surge? My opk instructions says that the control line needs to be as dark as the test line and mine never got quite that dark, but I've heard some women's never do. I guess my questions is, Does this look dark enough to be a surge or should I keep testing?? Thanks in Advance!!