Maturity

Dear scholars, As-Salamu `alaykum. What is the age of maturity (taklif) for boys and girls? Can we say that a nine-year-old girl is mature enough to fast and perform daily prayers and to be perceived as mature? Jazakum Allah khayran.

Respected scholars, as-salamu `alaykum. Can a young youth, aged 13 years old, lead the Tarawih Prayer? He knows the Qur'an by heart, is a good reciter, and understands the rules of Tarawih Prayer. Jazakum Allahu khayran.