https://en.wikipedia.org/wiki/Age_of_majorityThe age of majority is the threshold of adulthood as it is conceptualized (and recognized or declared) in law. It is the chronological moment when minors cease to legally be considered children and assume control over their persons, actions, and decisions, thereby terminating the legal control and legal responsibilities of their parents or guardian over and for them.
https://en.wikipedia.org/wiki/Age_of_majority#Age_20Ergo, You 20 Bitcoin Forever (or something similar).