No. TNG is a family show, one of those programs which can appeal to all ages. I loved it as a kid, I love it now. True, its adult content doesn't really come in the shape of sex, violence and swearing; TNG's adult content largely comes from the various themes and moral issues addressed on the show. And, candidly, which is the more adult?
QFT. I was 11 when the show started and 17 when it ended, and at different ages I was able to find different things to appeal to me. There were elements I think I would have liked at a younger age (the aliens and the action) and some that I probably enjoy more now in my early 30's than I did at the time (the social commentary).
TNG is one of those types of shows that I wish we had more of today: one that truly had appeal to all age groups.