This is a typical behavior. Most do it because they like the smell or the texture of a fabric. If you let her go at it for a little while, she's likely to turn and start anointing on her back. It's nothing to worry about. Often it's the same case with a t-shirt--they especially love to tug on them when you're wearing them so be careful if she heads toward your armpit because sometimes they accidentally nip skin and that hurts. You just want to be sure it's a suitable material for biting, that she won't be pulling pieces off she could be ingesting. If the towel has a lot of loose loops on it, I'd try to discourage that and offer a stringless shirt that smells like you or something instead.
On a side note, loops can easily get tangled around hedgie feet so be very careful with the type of towel you choose to let her walk on. A piece of fleece might be more suitable.
Welcome to HHC and congratulations on your little girl.
