Check-in for air travel differs depending on your starting destination, your final destination, the airline you are flying and your travel day and time.
Boys continue growing until age 17 or 18. Boys and girls grow about two inches per year until they reach puberty. Then they each have a growth spurt that lasts a year or two. During the growth spurts, boys grow a little faster than girls. Girls reach puberty (on average) about a year before boys do. Girls also end puberty earlier than boys.
The increase in growth rate that occurs during puberty is driven by the body's increase in production of sex hormones: estrogen from the ovaries in girls, and testosterone from the testicles in boys. These hormones cause the skeleton to grow and to mature more rapidly.