Yes — CicloZone is for adults, 18 or over (or the age of majority where you live). If you're younger than that, you may use CicloZone only with the involvement and permission of a parent or guardian (an adult) who agrees to the Terms on your behalf.
In a studio
Studios set their own attendance policy in line with local regulations and their insurance, so a studio may allow younger riders in supervised classes. Check with your studio.
On your own account or at home
The 18+ rule applies to creating your own account and subscribing to the paid Personal Subscription. Anyone under 18 must have a parent or guardian involved, who agrees to the Terms.
App Store / Google Play
Apple and Google may also apply their own regional age ratings.