Under 18? You can play chess online for free. Irish Schools Chess Online, in partnership with MatPat has built a site for you: http://matpat.ac-rennes.fr/ireland/
Click on “sign up”, enter your details and you will soon be ready to play your first games. You do not need a MatPat ID of your school for this individual registration.
MatPat is a French organization which combines the work of a non-profit organization (écoles en ligne) with various official organizations, backed by the French Ministry of Education, around Rennes in Brittany.