@BettyNewbie1 No worries. In general, most NEW skills that are not associated with specific group of skills (Mental, Creativity, Physical and Social) can be taught to kids directly. Vampire lore is one of those skills.
In addition, consider having you kids go fishing if you are playing vampire families. Kids can fish and thus provide blood bags to your older vampires or even to themselves in the future. They can even make the bags with correct level of vampire lore skill. Same is also true for frog collecting that can be used for the same purpose. Blood bags made out of frogs are also more nutritious than fish blood.