How long does a caution stay on your record?

ok so when i was 14 i got a caution for GBH, i was told that it would be on my record for a year and then it would be wiped. i have to get a police check before i can work in a nursery and a few people have told me that this caution will show up because i will be working with chidren. is this true? btw i did not actually cause anyone grevious bodily harm it was just a stupid fight between me and me friend, although i know that doesnt matter! i still got the caution!