There is nothing in the rules specifically that says "you may not be below [insert age]". Technically Feral Heart is aimed for people 13+. However, FH is full of many young players, some even below 8. I wouldn't say that your friend can't play Feral Heart. Simply make sure she watches what she does, what she says, what she posts, etc. Following the rules and such apply to everyone. Also be sure she knows that it IS the internet, and she might hear some things her parents wouldn't completely agree with an 8 year old hearing. Probably get a parent to give her the 'okay' before downloading/registering. Overall, your friend should be more than welcome to register and play. <3