You can talk to her in private about "the strangers of the internet" if you're worried she's at risk. Educate her on the importance of being safe and not giving out personal information. Educate her about stalkers and creeps and the not-always-altruistic motivations of others, especially men who might try to talk to her. You won't always be there to protect her; it's more important that she learn how to protect herself than for you to pre-screen every possible threat.
Hi, There are plenty of special parental control apps nowadays and I believe you can find among them the one that has such option. I personally use the mspy Parental Control app. First I read a lot of positive reviews about it and only them got it for my teenagers. It controls which apps can be used and when on my child’s smartphone. It is enough for me as far as web surfing is concerned. As for some extreme conditions mspy helps to monitor kids locations. I highly recommend it to any parent who is concerned about their kids` future.