At our last homeschool convention, David Quine made a really good point about technology: he said it is used as a tool NOT as entertainment. That has helped alot in our home. My 14 yr daughter does not have a facebook page. I used to have one, but I myself have a hard time managing my computer time so I stopped using FB. My dd doesn't have a cellphone, though if she is babysitting, I will give her mine. She emails with a few girls but all of it goes through my email, so I read it first and then let her know she got an email. But she's never given me a cause for concern. I like to check the emails first because sometimes the emails come with a link to a youtube video and I like to check the junk on the periphery of the videos if you know what I mean.
I do know my daughter's friends very well, and for the most part they all have good character. My daughter, so far, has proven trustworthy though she is not allowed on the computer by herself or she asks for permission first. I do feel like they need to learn how to handle these things that are part of our culture, but with much supervision and only if there is no rebellion.
In our previous church, the girls at age 11 had all those things and were very into them and boys. Now, at our current church, there is a great group of godly, normal girls who use these things but with the values I described earlier. They are pretty responsible, very respectful of their parents, and have demonstrated good character. I'm so grateful my daughter has these peers and examples. We moved 2.5 hours to make it possible. The Lord paved the way before us.
My point is, that the use of these "tools" really depends on your daughter's character and trustworthiness and on the character of the friends. I would rather her learn in time to use it in your home, than to sneak it when away from you. But it has to be earned. Hope this helps! Betty