Leggings? Appropriate or not? I can't decide...

What are your thoughts? So, I'm almost 30. I don't have the perfect body but I like to layer leggings with a long blouse/tunic. A sweet co-worker of mine (who is 10 years younger than me) admitted that leggings are for teenagers and that's it. I love her honesty. But I also like leggings. And my other concern is, are leggings too revealing? Too "Naughty Sandy" from Grease? Do tell.