Don’t Bite The Sun by Tanith Lee

In a far-future, post-scarcity society where engineered longevity has produced a pampered, risk-averse populace, a restless young woman grows disillusioned with endless leisure and perfection. Craving authentic feeling and consequence, she deliberately flouts taboos, seeks out danger and forbidden experiences, and challenges the complacent social order. Her rebellion forces her and those around her to confront what gives life meaning—freedom, love, identity, and the value of mortality itself.