What are age ratings?

Age ratings are systems used to ensure that entertainment content, such as films, videos, DVDs, and computer and video games, is clearly labelled for the age group for which it is most suitable. Age ratings provide guidance to consumers to help them decide whether or not to buy a particular product.
In the UK, age ratings for computer and video games come under two separate but totally complementary systems: the voluntary European PEGI system, which stands for Pan-European Games Information, and the mandatory BBFC system, which stands for British Board of Film Classification.
PEGI is used and recognised throughout Europe and has the enthusiastic support of the European Commission. It is considered to be a model of European harmonisation in the field of the protection of children. Already more than 7,000 games have been PEGI-rated since the scheme was devised and introduced in early 2003.

Essentially, the PEGI rating on a game confirms that it is suitable for a certain age group and above. So, a 7+ game is suitable for everyone over the age of seven while an 18-rated game is deemed suitable only for adults.
When buying a game for anyone under the age of 18, always look at the age rating to check it is suitable for the intended end-user