first time using opk

Alannah • Wife and mother of 2 boys 10/02/13 and 03/09/19 and 1 princess 05/17/21

so this is the first time I'm using opks and I'm supposed to be in my fertility window right now but every opk I take I only see a control line shouldn't I be seeing a faint test line by now? sorry don't have any pics of the tests that I've taken.