First time using OPK

Lauren
I just finished my period yesterday (my first natural period after stopping BC). I'm on CD6. Cycles are usually 28-32 days. Took my first test yesterday (not fmu) and the control and test line looked about the same color. Today I took one with FMU and the test line is clearly darker. Would I be ovulating this early? Or should I not be testing with FMU? Thanks!