Well, according to the snake measuring program my snake is roughly 13.9-14.5 inches long. The 13.9 was the first measurment and the 14.5 was the second (just goes to show that the software isn't perfect; that is unless you have a PERFECT picture that is completely flat and not taken at an angle) and last month it was roughly 11.7 (it actually went down somehow from 11.9)
So, in summary, it's grown at leat 2 inches in one month
(I've taken the pictures every fifth of each month)