At what age does praying become fard?

At what age are Muslims required to start their prayers? When does it become an obligation? It's said that, to be responsible for fasting, the earliest age is 9 for girls, 12 for boys. Is it the same for daily prayers?

For a Muslim to be held accountable for Islamic commands, the first condition is to “reach puberty.” A mukallaf (accountable) Muslim is responsible for fulfilling the Islamic commands and abstaining the prohibitions which are classified into the categories fard (obligatory), wajib (compulsory), sunnah, mustahab, halal, mubah, makruuh and haram.

 As the first condition to be accountable for all these commands is reaching puberty, Islamic responsibility is quite relevant to the age of puberty.  The earliest puberty begins with the age of 9 in girls, and with the age of late 11 in boys.  Islamic responsibilities start right along with the signs of puberty. There is no Islamic responsibility for those under this age. (Tajrid Sarih)

"According to Imam Abu Yusuf and Imam Muhammad, the last age of puberty is 15 for both girls and boys. (Majalla)

 Fatwa of Hanafi Madhab is also parallel to this view.  Shafi and Hanbali Madhabs are also of the opinion that the last age of puberty is 15, while the view of Maliki madhab is 18." (Islamic Fiqh Encyclopedia)

As understood, worships such as fasting, praying become fard after reaching puberty. If there is no sign of puberty, the worships become fard beginning from the age of 15.