Cycle length?

Ashley
TTC #1 , 27. I went off the pill in October, and my cycles have been extremely irregular. The average length for four cycles has been 31.5 days. Glow has AF coming tomorrow, at 35 days. Should I go ahead and take a test now? Don't want to take a test if it's too early and my period will be here at my longest cycle length to date, of 38 days. Any thoughts?