I would happily bet that the opposite of that is true. The special effects have aged too much for modern pre-college audiences? Sorry, that's just bizarre. Lucas has gone back and tampered with the effects more than once since they were originally released and in any case, the orginal effects still hold up very well.
In the event you're right, any I don't think you are, the new trilogy will introduce that new generation to Luke Skywalker, Han Solo, Princess Leia, Chewbacca and the rest and as soon as they walk out of The Force Awakens, the original trilogy will be there waiting to enthral and entertain them and take them back to where it all began.
But, unless the milennial generation have spent their lives living under a very, very large rock which has stopped them having any access to a TV, the internet or contact with anyone who has seen the original trilogy, the majority of them will already be very familiar with those characters and the events that have led up to this exciting new era in the saga. And I'm sure many of them will be amongst the millions like myself waiting in line to be the first to see the new film.