Should I ask to sing a solo? What should I do?

In my school choir, we are doing a medley from Les Miserables, which includes quite a lot of solos. In practice, my teacher told us we would all get the ability to audition for solos, and I was quite prepared to do so. I have never sung a solo at school, but have sang quite a few in my other choir. He also said he was going to cast people who don't usually sing solos. Most people he has cast have all sung solos before, and no one got the chance to audition. There are 2 solos he hasn't cast, and I was wondering what I should do. My friend told me to tell him that I am upset, and say that I would like, in the future to sing solo. My mum told me to ask him jokily in my music lesson what happened to the auditions. I'm not sure. I really want to prove to him that I'm good enough, as he hasn't heard me sing for about a year. But I don't know what to do! HELP!