Do I have but any authority in the classroom?

Working in a school library is odd. The line of the level of authority I have is somewhat blurry. I’m a member of staff, yes. However I’m not a teacher. I personally struggle to know what to say when a pupil misbehaves, as I’ve never had to tell anyone off in my life. I have no desire to teach, but there are occasions when I’m supervising a library, or have been called to supervise a prep session, and I just pray that everything will go okay, because I’m genuinely not sure how the students see me, if they even know who I am at all. For example, the students are not supposed to eat in the library. They know this. However, as I was sat at the staff computer in the younger year library, I heard the distinctive rustle of something wrap-ery behind me. I didn’t turn round, as it can often just be folders, or papers rustling. Then I heard this:

Student 1: “Ahh, you have Jelly beans! Can I have one?”

Student 3: “I’m allergic to Jelly beans”

Student 2: “How can you be allergic to jelly beans…?” Whilst passing around her sweets.

It’s just blatant cockiness. They know it. What I thought might be happening, was that they were testing me. I’m a new member of staff, maybe I don’t know the rules. Or seeing how badly I would react if I did know the rules. CC often throws out students who are eating. Do I do this? I was slightly concerned they wouldn’t leave if I asked them to, so I settled with turning round with raised eyebrows, and telling them firmly that yes, I can see the jelly beans and could you please put them away. To be fair to them, they put them away – not even up their jumpers to munch on ‘discretely’ and looked at least a bit sheepish. It’s not the biggest problem in the world – and I know I’m lucky in that the school I work at is not at all bad. I’d be more scared if I was working at my old high school to be sure. The level of misbehaviour would be way worse and happen far more often. But I just need to establish a level with the students. Yes, you can come and ask me questions, I’d like to remain approachable, but I’m not taking any of your cheek (and that’s exactly what it mainly is. These student’s aren’t really misbehaviours, they’re just a bit cocky sometimes) and I’m not a pushover. Like Neil Gaiman says: Don’t f*ck with librarians. Maybe there’s a good book on the subject…