Background Verification and Past Legal Issues
The case was disposed of, meaning you did not contest and paid the fine as ordered by the court. If that is so, then you are guilty, and in the case of a detailed Background Verification (BGV), this may be reflected.
Timeframe for Background Verification
Normally, BGV is done for the immediate past 5 years. Since this is more than 7 years old, it probably would not be highlighted. Nevertheless, in case the question is put to you, "Have you ever been prosecuted," it is advisable to come clean. As it happened when you were 14 years old, the incident can be explained satisfactorily.