Solution for my Haircut Dilemma

The past days were bad. I had lots of exams and I had to do lots of studying and things didn't go well.
Anyway, I will try to live the joy of Christmas these days by attending the Christmas carols and joining the decorations efforts in the house.
I just love Christmas Time of the year.
Bloggers Meeting is next Sunday, cannot wait for it.
My hair is tall and according to my calculations and the stars and planets, and in order for it to look nice for the Christmas party, I must have had a haircut on the 7th of this month.
Now I have a long hair and it will be too short if I had haircut right now.
The only way to solve his issue is to hope that my barber is good at math and solving differential equations to be able to get the ultimate length of the hair based on the new 'haircut-day'
I think he has to master couple of probability and statistics basics too :-)