another question about the coolant system

when I drive my 94 taurus(3.8L) for 10 mintues, the temp may goes to 2/3 high of the gauge, and then the fan begins to work, and temperature goes down to 1/2 of gauge , the fan also stop working. But in the other people's taurus, the temperature is keptin 1/2 of the gauge constantly. I got confused on my car. Please help, thanks

Thermostat might be sticking or not opening all the way.