English: students' age and number at the lesson

 Do you know when is better to start English studying? 10 years old? Maybe 6? or later?

I started my own studying at school. I was 10 at that time.

Now beeing a teacher I can say that it depends on person. My older  student is 62 and my younger one is 4.

Is it better to work in group or eye-to-eye with your teather? In depends on your priorities and aims. But as for me group work is obviously better :)