Actually, waiting for 5 to 7 days after your missed period is ideal, yaar. It gives the best, clearest result. Testing too early just increases the suspense!
It is best to wait for 4-5 days of a late period before testing. If the test is positive, or if you have severe cramps or spotting, make sure you consult your doctor immediately.
Currently in my 3rd trimester and can barely bend to see my toes, but I remember testing at 3 days late. Save yourself the stress and wait at least a few days, those cheap kits can be tricky.