Is a Muslim woman who prays at home considered sinful if she performs the prayer a short time (fifteen or thirty minutes) before the adhan for the next prayer, and if so, what is the maximum time one can delay a prayer without sin?

It is not permissible to delay the prayer beyond its legally prescribed time, for Allah Almighty says: (Indeed, prayer has been decreed upon the believers a decree [to be observed at] fixed times). The last time for Dhuhr prayer is the beginning of the Asr time, and the last time for Asr prayer is when the sun turns yellow, extending for those in dire need until sunset. The last time for Maghrib prayer is when the red twilight disappears, and the last time for Isha prayer is midnight, and the last time for Fajr prayer is sunrise. Prayer is permissible at any part of its time, but it is best to perform it at the beginning of its time.