Yeast infection and drs?

So I told my mom that I have been itchy down stairs for the past few days. She bought me vagisil wash to see if that helps and then told me to tell her if it doesn't seem to help. Anyway, it stills itches so I am planning to go to the walk in care tomorrow to since my doctor won't call back and it is almost Christmas. Does anyone know what diagnosing a yeast infection includes? Do they have to check down there or can they just prescribe you something with just knowing your symptoms? Btw I am 13 and have never had anyone see me naked or seen down there. I've never had sex. I'm so nervous because I don't know what to expect, anything would help.