The problem about testing first thing in the morning is not that it is more concentrated, but that the LH is usually synthesized in your body in the early morning hours and therefore might not show up in your
urine until a little later. In other words, first morning
urine may show negative even though you are in fact having an LH rise. So, since you still got a line that was as dark as the test line with first morning urine, I would definitely consider that a positive.