When 2 of my daughter's best friends moved away (from Pennsylvania to Florida and Kansas) 1 1/2 years ago, we signed my then 7 year old daughter up for her own email address.
However, here are the stipulations we used...
*It is actually in my name.
*She is only allowed to email people who I know and have approved of.
*She is not the keeper of her password, I am. If she doesn't like that, she doesn't need to have email at all.
*She does not log on to her email without me right there.
*When she wants to email her friend, she types of the email message in Word, Wordpad or Notepad. Then together, we copy and paste the message into the email program online (we used AOL's AIM).
Basically, I treat it as a privilege that is not granted complete privacy. She should only send or receive in a message information that she is not afraid to have me read. She is not allowed to chat and is not allowed to surf the web randomly. We have a list of sites she is allowed to visit and a list of people who she is allowed to email.
It is not that I do not trust my daughter, and I have explained this to her. I do NOT trust some of the predators out there on the web. I do not want her opened up to these people. I want her to be a safe and happy CHILD for as long as possible not sullied by the sick fantasies of some of the people who use the web to prey on others. Don't get me wrong, I love the internet. I think it is really useful and can be a wonderful way to communicate. I just also recognize that it can be used to do irreparable harm to others as well.
Anyhow, that is how we handled it. Before she had her email address, she would sometimes get an email message from her aunt (who lives several states away). We just asked her aunt to send it to my email address with the subject that stated it was for my daughter. You could do that as well and skip the email address part for now.
Whatever you do, please stress to your daughter the dangers of speaking with strangers online even if you decide to forbid her from emailing people she doesn't know. She needs to know that there are valid reasons for the limitations you place on her. She needs to know that there is a real danger out there and that these rules are there to protect her from it.
Anyhow, I hope this helps. Best of luck with your decision.