1987 Mazda RX7 break pressure

Brakes problem
1987 Mazda RX7 4 cyl Two Wheel Drive Manual

i have a 87 mazda rx7 gxl and when I push the breaks the car doesnt start to slow down until the pedal is all the way down. I had it inspected and turns out im getting more pressure n the rear than in the front. My questions are: is the lack of pressure the reason why I have to press the pedal all the way down inorder to slow sown or stop, and what do I do to fix this?