My club in Northern NJ does something a little different. We have no "junior" memberships for outsiders, rather the kids of full members are "juniors" from 17 to 28. They pay basically little dues during this time. Come 29, they become "legacy" and pay their bond and initiation amortized with no interest for 15 years, with suppressed dues and no voting right at the time.
The biases in me enjoys this, as I have an interest free loan for 15 years. However, I would like to see the club to make strides to invite younger families to grow it over the long term. We do have a full waitlist however.