I'll echo what Pug said. A lot of people are very touchy feely types, especially a lot of females i've encountered, which is fine, as everyone's different, but on the flip side there are people who like their personal space.
For me, I like my personal space. Unless the girl touching me is a a girl I'm interested in sexually/romantically, then I'm probably not gonna want someone touching me unnecessarily. To me it definitely seems a bit soon for her to be doing stuff like that and I don't blame you for being uncomfortable.
I hope all goes well with your message to her! I'm sure if you explained it delicately she'll understand.