According to Osho, constant thoughts about women are natural; repression and inherited guilt from parents, priests and society make them obsessive and joyless. Don’t fight them—accept and live sexuality consciously and without condemnation. Enjoyed fully, it ripens and naturally wanes (often by midlife); only enlightenment ends it completely. Suppression breeds persistence and perversion.
It’s normal to think about girls; feeling guilty and trying to stop makes it stronger, while relaxed, respectful acceptance lets it settle on its own as you grow.