I have no problem with children of all ages being exposed to it. If the very youg children's parents do not approve, they can certainly request their children to not be a part. As they get older, they can choose for themselves to opt out.
In the mean time, a good percentage will take it seriously, as, IMHO, they should.
If Civic Duty is your concern, why not take the "Under God" out and restore the Pledge to the pre-1954 non-Knights of Columbus version? That one was all about Allegiance to the country and nothing to do with religion at all.
Last time, it barely caused a ripple here and we still said the Pledge. I hope it will be the same this time. Michael Newdumb has too much time on his hands.