What is the right age to introduce kids to our epics? Or it is not required at all to introduce them to mythology, considering the fact that we don't know it existed in reality or not?

it is absolutely up to you, whether or not you want your kids to learn about the epics. in fact, i am just reading two books - Sita and Jaya by author Devdutt Pattanaik - a superb mythology writer. the books are a re-telling of the Ramayana and the Mahabharata, with a scientific and social twist to it. i am in fact planning to share it with my 10 year old as well. depending on your child's age, you can introduce some new retold versions that kids will enjoy also, mythology has nothing to do with religion, unless you choose to look at it that way. we are an atheist family, but these mythology retellings are more scientific and about social behaviour than about 'god'