Youth Basic Act Article 2

In this Act the term “youth” and the term “young people” both refer to citizens who are between eighteen and thirty-five years of age. If other legisation has provisions that use these terms to refer to people of a different age range, the provisions of that other legisation apply to people within that different age range.
中文原文 青年基本法第2條
本法所稱青年,指十八歲以上三十五歲以下之國民;其他法令就青年年齡之範圍另有規定者,從其規定。

English translation for reference only; the Chinese text prevails. Not legal advice.