No, invading a person’s privacy like that isn’t ok. If you want to keep tabs on her facebook account, tell her that you will check her account once a week or something. Yes, she’ll hate you for it, and will probably be able to hide some of her activities from you, but at least her confidence in you won’t be entirely betrayed. What would you do if you found out your daughter was snooping through your things, your someone else’s? Don’t expect her to learn life lessons when you’re setting such a bad example.