..Neither? I don't personally know many Amys, but I picture someone in her late twenties, early thirties. It's a very simple, sweet name, and because of that I couldn't really see it as 'classic;' it doesn't have that flowing, vintage, intricate sound that a name like Isabella, Margaret, or Catherine does. Amelia is a classic, but not Amy. However, I couldn't see it as dated either, because I've never known a large number of older Amys.
I see it more as a staple name, one that is always there and everyone knows, but will never be extremely popular, like my name (Cecilia), or names like Kristen, Lisa, Abby, Anne...
I once answered to post like this and I will repeat: I love Amy!
Amelia became quite boring but Amy is so pretty, feminine and simple all in one. I think of Charles Dickens's novel or Little Women and it's such a cosy association...
Amy Elizabeth, Amy Charlotte or Amy Catharine would be a fine name but to brighten it up, I would pair Amy with something a bit unusual but not unique or trendy. Some ideas:
Amy is a classic. We tend to think it is dated because of its popularity in the 70's.
I think it's a bit dated.