It depends on which site is providing the service. I got my first email account almost 9 years ago. I got it when I was 7 (I don't think there were any age limits at the time) because my cousin in Nova Scotia wanted to talk to me via MSN. As far as I know, there is an age limit on Hotmail, but you'd have to find out how old he/she would need to be. I'm not sure about Yahoo or Gmail.