How early should i test.

Iv been trying for 3 yrs. im 4days late. When should i test? I dont wana test to early as it could be a bfn then maybe i actually cud be in few more days later, im also scared of it being a bfn, but its so hard to wait more days to take a test. Ttc is so hard enotionally. If af is stil coming i just want it to happen now to get this disapointment over n done with ?. After 3 yrs iv got so many mixed feelings.