I think it would be better to have your first swinging experience with an experienced couple. An experienced couple will understand any nervousness or hesitations you might have, and may know a thing or two about how to get past that! People who have done this before will probably be better at making the sometimes-awkward transition from talking about your jobs and kids, to getting naked and playing.
By contrast, another newbie couple could be fumbling around, unsure whether they even want to do this. The potential for a last-second change of heart or a burst of jealousy (also known as drama) is doubled with another new couple involved.
So in my opinion, it is much better to let an experienced couple, who is sensitive and respectful, show you the ropes. Good luck!