Yep. Please bring some proof of age when they come to the festival. They will also need to be in the company of a parent or adult guardian at all times.
Anyone over 12 needs to purchase a ticket. Parents/guardians will need to provide proof of age for those aged 12 or thereabouts who may be mistaken for 13 or 14. Those aged 13 or over must buy a ticket, and of course be accompanied by a parent or adult guardian at all times.
We have to adhere to a legal capacity limit and everybody on the site (even if they're only small-ish bodies) counts towards that total.