Many 14 year olds are responsible enough to babysit for a few hours - however, you would be hard pressed to find find someone who would employ a 14 year old stranger so, same as above replies, try any animal shelters etc
You may even consider voluntary work too which always looks good on a CV when looking for paid employment
I agree with bigmamma, how lovely to see a polite young person although I met another this morning when he let me pass on the non icy but of the icy pavement and when I said thank you, he replied 'Not a problem luv' :)