You ARE psyching yourself out, lol.
REad the middle of the flow ball.
CO2 is an art; if your flow is slightly higher or lower you are not going to have a problem because of that, don't fret.

The only thing is that the flow ball is supposed to drop to the rest position when the solenoid clicks off at the end of 15 minutes. If you feel CO2 still releasing from your hose, you have a problem- bad timer or solenoid valve, or your plumbing is incorrect.