No, there is no age limit for trekking in Nepal. So, anyone with functional physical fitness can go trekking. Children older than ten years, as well as older people, can go on a natural or moderate labeled trek. However, the difficult labeled and strenuous treks are not suitable for young children and older people. If you have children under age 10, porters can be arranged to carry them throughout the trek. Also, a unique itinerary can be arranged for groups with older people and children.