Must the prayers be repeated that were performed inadvertently without the first Tashahhud in the Fajr prayer, along with the doubt regarding the number of these prayers?

The first Tashahhud is not recited in two-unit prayers, such as the Fajr prayer and supererogatory prayers performed in pairs of two units. Rather, it is only recited in four-unit and three-unit prayers, such as Dhuhr, Asr, Maghrib, and Isha. The questioner's prayer is valid if she performs Fajr prayer with one Tashahhud, and her prayer is also valid, with no need for repetition, if she mistakenly added an extra Tashahhud out of ignorance.