Lane Bryant has all sorts of sizes, and quite tasteful without being 'old' IMO. (well, ok, some is 'old lady stuff' but not all.) I'm not small at all, and since I'm not a teenager either, I struggle with finding the right balance. I don't want granny gear, (though I could be one! LOL ) but I don't want to look like I"m trying to be a kid either.
My worst problem is shoes. I have some big ol' feet, though, since I'm also very tall, I joke about the fact that "If I had little feet, I'd tip over!"
I guess my point is, get some basics, that you can dress up or down, or can funk it up a little too, splash with color or some cool jewelry! Find what you are comfortable in, and go have fun! Better you go and decide it wasn't worth it, than NOT go and always wonder! ...I usually find a way to enjoy myself!
I'll bet you can too!
Oh, and for any tall ladies out there, this is a great place with good solid basics, and good customer service. I only had one problem with a pair of pants, and when I called about it, they sent me new ones before I even sent back the damaged ones!
http://www.tallwomensclothes.com/