Well its hard to judge. When I first listened to New Order in 1997 the stuff sounded more dated to me than it does now. It sounds more unique now, in the end its the feeling in the music which is going to come across. I remember Fine Time sounding exceedingly bad the first time I heard it, but now I enjoy it for being tongue in cheque fun.
New Order have a lot of respect with people of all ages I think, Get Ready definitely doesn't sound dated I don't think, it sounds uniquely New Order, but one definitely fit for the New millenium. Take for example here in Australia for Triple J's hottest 100, which is a station basically for young people and people into alternative music I guess, and 60mph and Crystal were both in there, the later being 36 or so.
As for teens, well who cares? The majority of teens at any time will like whats trendy at that particualar time and that will happen forever.
Cheers
ALEX