not sure im doing this opk right


ok so ive never tracked my period, ovulation nothing. I got off bc and had my first period on the 4th. it stopped on the 8th ( that's normal for me) well ive started using opks 2 a day since I have NO IDEA when I ovulate or even how long my cycles are. My question is is it ok if I don't take them exactly at the same time every day? I like to take the first at about 6:30 am and the night one at about 7:pm but sometimes I don't take the morning one until 7 or ill take the night one at 6:45. is that ok? its hard to do it exactly at the same time because I have three kids 2 dogs an a husband ( which makes a 4th kids). I'm sometimes to busy or the bathroom is taken.