Paris Pass - Necessary for teens?

The Paris pass is a terrible idea -- it is ordinary products like the Museum Pass and the worst transport product the 'visite' tossed in an envelope with some coupons for other experiences most of which you can't get done in the time you have.

If you want a museum pass buy just that (it is not of much value as it has no benefits unless you will do a museum marathon and thus have a slight cost savings on museums) Kids under 18 just go to museums free with you. You need to reserve a time slot at many museums and some require that for the kid too -- do that on line. And note that the Louvre has very few slots for museum pass holders who often find no times available for pass holders when they are still selling tickets to those buying tickets.

for transport there are several options depending on your dates but a teen is an adult for travel except weekends when there is a day pass called a ticket Jeune which is a real bargain.

You want to avoid the Paris Pass completely. It is nothing other than a collection of tickets/passes which can otherwise be purchased at far lower cost.

Your grandchild may accompany you to many museums (you might consider the Paris Museum pass) but will not be welcomed to travel free with you on the other venues offered by the Paris Pass.