Test in the afternoon?

Joanna
So I'm about 5 days late, and while I'm not 'feeling pregnant' and have some light PMS signs I'm going to buy a test this afternoon. 
I know you're meant to test first thing in the morning but will I be okay to test this afternoon too? 
I don't think pregnancy will come so quickly to us as I have slight endometriosis but I think it's best to find out now as I'm usually only a couple of days late...