Testing early

How early can you test with a first response I'm due on in 6 days I've signs I'm coming on but also signs I'm pregnant my lb is 9 months old a year ago today a 24 weeks my waters broke does anyone no if I'm likely to Pprom again if I am pregnant my last baby is my 5th child I think my body has had enough of having babies but my partner i'm with now has no children please don't judge as life don't go to how we plan