Welsome to the world of popper roasting, Paul!
If youve never had fresh roasted coffee at home, Ill tell you this is NOT too fast, and youll be VERY pleased with the results!!!!! On the other hand, if you have a local roaster and have grown accustomed to his fresh roasted coffee... yes, this is quite fast time.
IF, after a few days, you grind and sip the cofee and say to yourself, "I dont think this tastes very good," (unlikely!) then here are the 2 things you can do to slow the roast:
1) roast with less green coffee. *This will let the air flow faster through the beans, lowering the temperature.
2) do not use the lid of the popper. *Let the hot air go straight up rather than some of it blow down to preheat the air taken into the roaster.
After your first cup of home roasted coffee, tell us about it! *Best of luck!