Any of us, even those of us who have been shooting a long time, could change our draw length by an inch (+ or -) by changing our alignment, the extension of our bow arm, or the rotation of our string arm elbow. The goal is to establish a repeatable draw length that will accurately put an arrow in the same spot time after time, which is different from the maximum draw length you could possibly achieve by stretching everything to the max. OTOH, as you progress, you will probably find ways to extend a little more without sacrificing the accuracy of your shot.
As a beginning traditional archer, you should expect that your draw length will change over time, and not worry about it.