Not normal. With the stock size master cylinder the pedal will be hard but you shouldn’t have to “stand on it” to come to a stop.
The “usual suspects” have already been recommended as far as troubleshooting goes. What year is your car? Are the disks original to it?
I prefer manual disks on these cars over the factory power systems. I switch them over to a 15/16” bore master cylinder (makes the pedal effort a little better). The pedal effort is nothing like a new car if you’re used to that, but it shouldn’t take anything extraordinary to make the car stop.
