I'd hold off until you get your second snake. You didn't mention how soon you thought you'd be getting a third or fourth snake. Usually it's not worth breeding rodents until you have at least 3 snakes, but I suppose you could get started if you get a second one with plans on getting more.

Also, will you be feeding live or F/T? If feeding F/T, you can always freeze the surplus for when you get more snakes.