Do I sound okay(video link)?

I'm just getting over a cough, and I'm meant to be performing Kelly
Clarkson - Because of You at a talent show on Friday. Does it sound
okay to you?
There are a couple of times where I go off key a bit when I try to
hold back my cough.

http://www.flickr.com/photos/60829311@N03/5869515189/in/photostream

Constructive criticism please?
I know my voice doesn't sound 'mature' but I'm 13, so it probably
won't for a few years.
Thanks in advance:-)