Firstly I think I would point out to Miss that your interview with a bullied person would be very informal so as not to add to the stress and distress the person is already feeling so....comfy chairs not table and chairs set up, maybe a cup of tea or something similar are you are trying to put the person at ease. Then introduce yourself and possibly find out a bit about the person. I would then ask them to tell you what has been happening - it is fine to go back over what they have said to ensure that you understand the situation. I would want to know who they have told and who they think could support them. I might ask them if I could help them tell their parents....and take it from there....It is always worth working out, before you start, what you want the outcome to be...support the victim for example.