Will the female questioner be rewarded for completing her father's building construction with her own money and with her full consent?

A Muslim is rewarded for their intention, even in permissible acts, as the Prophet (peace be upon him) said: "Deeds are only by intentions, and every person will have what they intended." So, if you spend your money willingly and with a good heart on this endeavor, seeking reward from Allah by showing kindness to your father and siblings, then you will be rewarded.