Has she put on weight recently? Might just be a growth spurt?
Just to be on the safe side though I would check her for signs of mites. They sometimes shed more frequently when they are being irritated by the pesky things.
How old is she? Like Kaz says, it could just be a growth spurt. My corn snake is doing that at the moment as well, although in her case I think the growth is in girth rather than length
1.0.0. Western hognose (Baldrick) 0.1.0. Amel bloodred corn snake (Cornflake) R.I.P. Bob (Western hognose)