1. As everyone else says, she is well aware. 2. Really depends on person to person and the best thing to do is ask! I was just at a stuttering conference and one talk specifically mentioned a survey done with stutters and how differently people can feel about this! Same goes for maintaining eye contact. Some prefer that, others hate it.  3. I personally often disclose it to people but rarely before I meet someone. For example, I always disclose it at the beginning of a job interview or in class to my professors and classmates. When I interact more casually with people, I would often say that I have a stutter if I start blocking really bad, so that people are aware. Never had a bad response and I love educating people and bring more awareness to the issue! I have to say I am in my thirties an it wasn’t until recently that I started doing that, it took me awhile to get comfortable with the idea and at the beginning disclosing felt terrible, but now I don’t even think about it.  If you are willing to have a conversation about it with your friend, you might literally be the first person she will ever talk about that with, and that can be life changing! She might also be mortified at first lol. But I would say it’s worth it, just plan how you would approach the topic carefully and be ready for her to resist the discussion at first! She is lucky yo have a friend like you!