The Jiyushinkai syllabus doesn't allow any joint locking techniques before 13 years of age. From 6 through 13 there are lots of drills and games containing kihon (principles) which emphasize posture, movement, ukemi, balance breaking, lots of judo type throwing and groundwork.
After 13th birthday, the student enters into the regular curriculum. No one is promoted to shodan under 15 years of age (and that is the exception).
If a young student has grown up in this practice, they are more than capable of shodan level sometime between 15 or 16 years of age.