More than likly you will be tested wether you are 18 or not. It really depends on you lawer, judge, and PO officer.

I would not try to dilute or in any other way tamper with your specimen if you are on probation. Further more you will probably have a month before you have to report to your PO officer, so that can be your "clean up" time.

I was charged with possession of cannabis and a pipe about 3 years ago. I took the diversion plea and had the charge removed from my record. I had to serve 11/29 probation with random drug tests....it sucked, but I stayed clean.