Under 12 years old is calculated as 11 years old.
To buy children’s tickets, those over 6 years old need to purchase a ticket.
Sure, I have asked the Disney customer service, and my family has just gone there.
Disney children’s tickets are based on height.
Standard Ticket/Children’s Ticket: Age between 3 years (inclusive) and 11 years (inclusive) on the day of visiting; or height between 1.0 meter and 1.4 meters (inclusive of 1.4 meters).
All those under 14 years of age are considered children.
What ticket should I buy? Anyone under 14 is considered a child, but some tickets require a height check. Check the ticket purchasing policy for the ticket you want to buy.

Under the age of 12 can be considered a child.

Now it’s time to buy adult tickets!!!!!!!
According to the Railway Passenger Transportation Regulations of China National Railway Corporation, children under 14 years of age can purchase children’s discount tickets, and those aged 14 years or older require full fare. Hope it is adopted.
Child tickets for ages 3-11, 12 years and up are considered adult tickets.
Under 12 years old is counted as 11 years old.
To purchase a child’s ticket, one must buy a ticket if over 6 years old.
Sure, I’ve asked Disney customer service, my family just went there.
Disney’s children’s tickets are based on height.
Standard Ticket/Child Ticket: Children aged between 3 years (inclusive) and 11 years (inclusive) on the day of the visit; or children with a height of 1.0 meters and above to 1.4 meters (inclusive of 1.4 meters).