At my classes there are a group of four yellow belts all in the same age group of around 11 to 13. All of them have been doing Aikido for longer than me, however, I cannot help thinking that I am a more experienced student, despite being a white belt. Their attitude towards the art is less serious than mine, although I realise this comes with age. I have trained with them on occasion, and it has only served to reinforce this belief of mine. But, then again, perhaps I shouldn't be so focused on others' paths, and instead I should keep my eyes straight ahead on my own goals.
For my advice to you, I don't think there's anything you can do to help them except maybe let them learn from their own experiences - finding out for themselves where gloating will get them.
[Edit - typos