Lala, give it a try and post pictures. I think this look is great on any age. It's all about how you wear it. I'm guessing if you're wearing a Tory Burch dress you aren't going to look silly at all.
I love leggings (it took me a while to come around, but when I did, I really did) and have worn a black microfibre pair that are actually long underwear (I got them at Mark's Work Wearhouse, for the Canadians in the house--$20 per pair) all winter long under dresses, with boots. Yesterday I wore an oversized grey turtleneck sweater over them with my brown Frye Paige boots. It was so comfortable, cute, and warm.
In the spring and summer I love leggings with tunics or dresses and flats or sandals. They're great for spring especially because they add extra warmth.
My rule for tunics and dresses is that they must cover my cheeks completely when standing and when i bend over (this depends a bit on the amount of volume in the skirt and how loose or tight it is--looser or more voluminous skirts or tunics leave a bit more wiggle room). I do not want to leave the house looking like I forgot my pants. That's my biggest fashion pet peeve!