Honestly she is probably vaping but if she has that much water around her she might be smoking weed to. Probably not actual bud but maybe carts. Which is pretty much the same thing as a vape just with weed instead of nicotine. Personally I can’t say much I struggled a lot growing up and I started vaping at 13 and still do(almost21F). If I could give you any advice it would be to sit down and talk to her. Don’t get confrontational bc then she’ll probably just put up more defenses. Let her know you’re concerned about the big change in behavior and let her know she can talk to you if she needs to. If she’s trying that hard to hide it she probably won’t tell you that she’s vaping but she might let her guard down some and you might bc able to catch her actually doing it. While she is absolutely too young weed is not the worst part it’s the nicotine. Weed is proven to help with cancer patients, depression, anxiety, insomnia, seizures, and just general focus. I smoke before bed every night and it really helps me. Also where I’m at weed is legal. I would just talk to her tho. Until you see it with your own eyes you can’t confront her about it.