That’s not the definition of homosexuality. Go to any doctor/medical office, employment manual, survey, and legal document. None whatsoever refers to the illustration you are proposing. Thus, not what it means. You are driving at a motive on the suggested tendencies/sexual preference for people of the same sex to justify the act/behavior. But, it doesn’t acquit the definition from the preference of males preferring boys (whether you define that as immature or not.) The fact/basis is that men who prefer boys are homosexual on the subset preference from the definition itself.