Trying to decide when to test

I use 3 different apps; Glow, My Days, and Ovia, and usually they each give me the same date for when to expect AF. But this month they each gave me separate dates, the 23rd, 24th, and 25th. Normally my AF starts 21 days after the last one ends, which would have been the 22nd this month. So now I'm trying to decide if I should keep waiting for it, or if I should test in the morning.