Positive OPK test??

Hey y'all, this is my first post, though I have been lurking the boards for a while. 
My husband and I have been TTC our first together since July. I'm 28 with no children, he is 42 with a beautiful 6 year old. This is our 8th cycle and I am starting to get worried it will never happen. 
I have been tracking my periods and ovulation predictions with the app, but this is the first cycle I've used the OPK's regularly. I'm still not sure just how dark a positive is.
Let me know if you think this thing is positive, please!