Hair Testing, quick reply please!

Tomorrow (Thursday) I will do cocaine for the first time, around 4 PM. I am only snorting one line ("normal" sized i guess). There is a possibility I might get a hair test or urine test Sunday afternoon. I realize this is pushing the limit for a urine test, but given the small amount I am doing, and the fact that I have an extremely high metabolism, should I be okay? Also, I read somewhere concerning hair tests that it "is generally accepted that in order to test positive, the drug in question must have been used 3 times or more within the window of the test". However, I've also heard it can be detected up to 90 days after a single use. Which one is true? I know for a fact I will be drug tested again around August 14.

Should I be okay?????

 

Why not just wait until Monday to get high?