UPDATE 3:
First try:
Started Mac.
Opened AP.
Pressure not working.
Quit AP.
Second try:
Opened AP.
Pressure working.
Clicked on Pages to write this.
Back to AP.
Pressure not working.
Quit AP.
Third try:
Opened AP.
Pressure not working.
Quit AP.
Fourth try:
Trashed AP preferences.
Opened AP.
Reentered activation key
Made sure all tools are properly set for pressure.
Pressure not working.
Quit AP.