Does the clutch engage at all, meaning for a few short seconds, then disengages? This would be an indication of no pressure (loss or Freon due to a leak).
Otherwise it could be the pressure switch, A/C clutch, or dash switch/connection to A/C clutch.
With a test light or multimeter, you could test the dash switch (A/C activation) by turning the key to on (don't start), unplug the connector that plugs onto the A/C clutch, and see if you have voltage. That rules that as the fault or not. If that checks good, then I'd steer towards a leak causing no pressure (and with this, the A/C clutch will cycle on/off over and over), or the pressure switch does not detect pressure in the system. You'd need gauges for this test.
It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.