Age Appropriateness of La Pastorella .... ?

My 13-1/2 year old daughter is considering doing another Eisteddfodd next year (2011)...  (She is classically trained.)

She is learning La Pastorella at the moment - because she likes it - and we are wondering if she sang that next year at an Eistedfodd would she be marked down by the adjudicator because of the song?  Would it be considered age appropriate for her or not? 

I think for one Eistedfodd she will still be 13, almost 14 but on paper, she'd have to be put down as a 13 year old... the other one we're considering, she will be 14. 

We had a look at the English translation of the song and whilst I/we are not familiar with the opera from which it comes, the song itself sounds innocent enough - it doesn't appear to contain "adult themes"... still adjusticators are not created equal and what one seems to consider okay, another will get up in arms about...

So... opinions please... :)

thanks!