13th, 14th and 15th

Q: Which three days should one fast in Shaban, the 13, 14 and 15 Shaban or 14, 15 and 16 Shaban?

Q: Whenever the 13th, 14th and 15th of the month comes, my niece gets her menstrual cycle, so she is not able to fast during those days. So should she keep those fasts after her menstrual cycle or just leave it because she can't do it?

Q: An Aalim says: Traditional Eid-e-Milad-Un-nabi is Bid'ah. It is not Islamically right. But, it is true that Rasulullah (Sallallahu Alayhi Wasallam) himself celebrates the days Modays keeping Fast since it was his birth day, day of Hijrat, day of getting Nabuwat etc. I would like to know, if it is correct and if so, can we keep fast on Mondays like our prophet (Sallallahu Alayhi Wasallam)?

Q: I made a vow that if I commit a certain sin I will fast for 3 consecutive days. Unfortunately I fell in to this sin many times after so I have 27 fasts to keep. If I fast with the intention of these fasts on days that are virtuous to fast like the first 9 days of Zul HIjjah, 13 14 15 of each month will I receive the thawaab that comes with normally fasting on these days or will only my vow be carried out?