age upon joining

Hello, im interested in everyones opinions as to what age i should set on my site for joining, i keep changing my mind as whether to set it at 16 or 18... the site has no adult related content so i thought 16 would be fine. However i would like to cover myself for future hiccups.

I know facebook has over 13 policy...but browsing through some of the groups on there i noticed they're are some groups parents wouldnt want their kids to be part of ie drug parafanalia smoking etc.

I maybe over concerned parent but would just like some help or ideas ive not thought about.

Most sites use the tirthteen age for non adult sites. 
I use for my social site the minium age of 8 years, but children under 13 years must use the private option for the profile. 
As admins we check these accounts.

So its up to you own thinking, if you play on save, then use the age 16 or higher..

This was double posted 

Thanks for your reply, 8 yrs old though...as a parent i would consider that far too young for a child to be registering on a social networking site, call me old fashioned but my lad is nearly 13 and i still havent let him register on any sites yet and when he does it is my job to monitor and vet everyone he will add to his friends.

By the way im not having a go, hope you dont mind me asking a few questions.

So all your members under 13 are set to private profile so no one can see their picture name age etc?

Does that mean if someone joins up who is for instance aged 10 cannot search for friends?..or make friends with kids the same age or are they able to see under 13 profiles?

Can they search through the forums and read topics created by adults?

What happens to you if something goes wrong?