My older co worker is harrasing me 26M

This older woman who's about 62 has become really touchy with me, she constantly puts her hands on my shoulders or comments about my body. It's to the point where if there's a meeting and other co workers are clapping, she glances over at me to see if I'm clapping along & then darts her eyes away. She's always saying how good I look and how I'm such a smart young man, I know she has some mental disabilities but I still feel uncomfortable and I really want to report it, I'm just nervous that they won't really take me seriously.