is it MY fault if i want someone to go away?

So I usually go to this place in school called the haven which is like a safe place, and I have a couple of friends there I usually go to hang out with inbetween lessons or on my break, but there's someone who's really been annoying me but won't go away!

Initially, I asked my friends if they also found this person annoying but didn't want to tell them because they were scared of upsetting this person, and said that I should do it instead since they think I'm more outspoken than them. Usually when I tell people to stop doing something I come across as quite rude and it's gotten me in trouble before, so do I tell this person to go away myself, wait for them to leave on their own, or tell someone else to do it?