Fulfilling a vow regarding doing a certain action

Q: I promised 10 nafal everyday if Allah fulfills my wish. If I pray those nafals after 12 a.m would it be ok or would it count in the nafal of the next day? Like I pray those nafal after isha and it often gets above 12 while praying because I have waswaas regarding salah. Do I have to repeat these nafal? I always prayed after isha so it means that technically if I prayed on for example on 12 December it would actually be counted as the nawafil of the 13 and the nawafil of the 13th will be considered as the nawafil of the 14th so it would still complete the 10 days.