You're going to get replies that are all over the map. I went with around 5,000 based on nothing other than I felt like it.
People just do what makes them feel good. It certainly doesn't hurt anything to change it earlier, but the book that comes with the truck says to just not go over 10,000 miles or 350 hours between changes.
From the manual:
"Your vehicle is equipped with an automatic oil change indicator system. The oil change indicator system will remind you that it is time to take your vehicle in for scheduled maintenance.
Based on engine operation conditions, the oil change indicator message will illuminate. This means that service is required for your vehicle. Operating conditions such as frequent short-trips, trailer tow, and extremely hot or cold ambient temperatures will influence when the “Oil Change Required” message is displayed. Have your vehicle serviced as soon as possible, within the next
500 miles (805 km).
Under no circumstances should oil change intervals exceed 10,000 miles (16,000 km),
12 months or 350 hours of engine run time, whichever comes first. The 350 hours of engine run or idle time is generally only a concern for fleet customers."
I find nothing in the manual that says the first oil change is in any way different than any other.