Keep in mind the more you try to control her, the more she'll rebel. Try to keep an open line of communication with no repercussions if they tell you something they'd otherwise get into trouble for. Better to know what they're up to and be able to guide them than to not know and them do dangerous things eh?
Your girls are what, like 15-16 now? That's normal for girls their age to start transitioning into women. They may be smart girls, but they're not 'wise' as they've not had that many bad experience to learn from. As a man it'll be hard to teach them through examples of your own. Ask wifey to give them the sex talk. I'd also recommend getting them pepper spray from a local gun shop or off of ebay. It's only like 15-20$ per spray bottle.
Also, if you find condoms in their room I'd advise against confiscating them. My mom did that when I was younger thinking it would prevent me from having sex.....and well, you can guess what happened.