Feeling like the black sheep at work

Hello glow community just looking for advice.

I love my job most of the time and I’m also the oldest employee plus the most dependable but my manager gets under my skin, I snapped on her today because she got pissy with me when I was checking my phone for a second while I was on my downtime, but here’s the big thing, the young girls are always on there’s phones, like literally all the time but she just gives them the u know better speech and the second she leaves they are right back at it.

I was irritated about other issues today but she just hit the right nerve. Also I do talk to someone in our circle because they really don’t judge but I’m just really seeking advice on how to talk to her because I really don’t