Is it necessary for a woman to wait for half an hour after the Sunnah of Fajr and before performing the obligatory prayer?

It is better to pray Fajr with "taghlees" (while it is still dark), meaning immediately after its time has been confirmed to have begun, especially for someone who is not waiting for a congregation. Therefore, it is sunnah for the questioner, if she has confirmed the entry of the time, to pray the two rak'ahs of Fajr and then the obligatory prayer without delay.