Point 1:
Young offenders can't be cautioned. They can only receive a reprimand or final warning.
Point 2:
The vast majority of employers have no access to CRB checks. They're only available when applying for particular types of employment, such as working with children or vulnerable adults.
Point 3:
Up until fairly recently, police forces would routinely delete reprimands and final warnings from their database after a few years. (Following a court ruling, they now longer do so). So any record of your brush with the law might already have been deleted.
Point 4:
Anyone can obtain a copy of their 'police record' by submitting a written application to their local police force (with proof of identity), together with a fee of £10. Google the name of your police force (e.g. 'Metropolitan Police, or 'Suffolk Police'), together with the words 'subject access' to find further information.
Chris