Depending on the day of the week, 4:30 is considered "rush hour". Getting to the airport that time of day will take approximately 45 - 60 minutes. That is with traffic, but doesn't allow for accidents, etc.
Then dropping off car, taking luggage to check - in, through security, to gate. (Do you plan on stopping for food, restroom?). I would suggest leaving at 3:45 to 4:00