If the players and yourself have no preferences then I'd start with Wings of Glory WW1, it is quite a bit simpler than Sails and looks great. My kids picked it up when they were 6 and 7, I think they'd have found Sails harder. When we run parti games at wargame shows its noticeably quicker to explain the rules for Wings and to get people going than Sails.

Of curse, once they are hooked and they understand the basic concept, THEN you hit them with Sails