how old should they be for the internet world?

Mine started at the age of 5 and still use it now at 9. However at these ages they are not allowed to surf alone, but with me or their Dad with them. I know there are plenty of programs out there that make the net a safer place for children, but not safe enough. Maybe you could add the change she can only be one the internet with you and this will help.

i dont think so there is any age for start of use of internet. What is more important is that the user should know that it can be used both for positive use or negative use. So one should use it well.