(1) Salah and Sawm (five time prayers & fasting in the month of Ramazan) become obligatory when the girl and boy reach puberty.
(2) The time of Fajr Salah ends at sunrise. As the sun rises the time of Fajr comes to an end and Salah becomes Qaza if someone could not perform it. Then, when the rays of the sun spread, nearly 15 minutes after sunrise, the missed Salah can be made up.
Allah knows Best!
Darul Uloom Deoband