IMO, absolutely not. I am 27, so I fall in that under 30 crowd, but I can't imagine ever giving up my MAC. My mom is nearly 51 and wears it. Take a look at some of MAC's best sellers from the line:
Shroom, Naked Lunch and Satin Taupe Eyeshadows
Vanilla, Coco and Coco Beach Pigments
Hug Me and VGV Lipstick and Lipglass
ALL of the above things are neutral and appropriate for any age. Sure there are plently of bright colors (which, IMO, anyone can wear in moderation) and such, but there are plenty of other colors and products for those who feel more comfortable in more natural, neutral shades. I think that in every collection MAC puts out, there is something for everyone from 17 to 70