Some people don't like letting other people know things they are trying to accomplish until it is almost over. Having people ask how it's goind or cheering you on can put a kind of pressure on you because you don't want to fail them.Why is he embarrassed about joining a fashion contest? He's literally already done it before, and it's all he talks about. No one would be surprised at this point, let alone bully him about it.
Some people don't like letting other people know things they are trying to accomplish until it is almost over. Having people ask how it's goind or cheering you on can put a kind of pressure on you because you don't want to fail them.