I was groped and fingered in a public hiking trail restroom [FF]

I am 19 and I like hiking / running out doors a lot. There are plenty of mountain trails near where I live and many of them have enclosed & covered public restrooms in certain rest spots. This was a spot I had been to for many years. Usually I go alone. This time one of my mom’s friends asked if she could come with me. I knew her for a long time; wasn’t close with her but she didn’t seem like a bad running partner. She is in her late 40s, tall and very fit.

It was a weekday afternoon. There were very few people out. I was wearing these basic running shorts and a sports bra. The bra was new and there was this label on the back that was awkwardly attached and bothering me. A while into the run, we came up to a rest spot. I went into the restroom to remove it and see if I could tear it off or adjust it. I didn’t bother going inside a stall since the whole area was very empty and I didn’t expect anyone to come in.