All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Vowing to perform the obligatory prayer or any other obligatory act is pointless because it is an already decided matter and a commitment that is binding by origin. Some scholars stated that it is disliked or prohibited to take this kind of vows. Al-‘Adawi, a Maliki scholar said in his commentary on the explanation of Ar-Risaalah: “We said that vows are specific to recommended matters so the obligatory matters are excluded. Al-Kharashi said: 'Is making a vow to do an obligatory matter disliked or just contrary to what is better?'”
Base upon this, your vow is not valid and it thus becomes clear to you that the prayers that you perform are the prayers that are principally imposed upon you, like (all) other Muslims.
You should adhere to fearing Allaah Almighty, preserving His obligations, and performing voluntary acts of worship and righteous deeds, as much as you can.
Allaah Knows best.