Mechanic Q: When should 1st oil change be made?

I bought 2008 Mazda CX-9 with 250 miles on it July 20, 2009. It now has 4250 miles; I drive more city than highway miles.

A: When should 1st oil change be made?

Thanks for your answer!

Mechanic Q: When should 1st oil change be made??

Purchased 2008 Mazda CX-9 with 250 miles on July 20, 2009. Now have 4250 miles. I drive more city than highway miles. Should oil changes be by # of months rather than miles if I only put about 1000 miles/month on it?