If you only received a warning or participated in an extrajudicial sanctions program, you probably do not have a criminal record. If you appeared in youth court and received a sentence, you may have a record.
Youth records do not normally last the rest of your life. Most offences are removed from your criminal record after a crime-free period. If the charges you were in court on were dealt with by summary conviction proceedings and you have no subsequent convictions, the charges should be removed from your record three years after you completed the sentence. Indictable offences would normally be removed five years after you completed the sentence if you have no further convictions in the meantime.
If you continue to break the law the record could stay with you until you meet the crime-free criteria. If you never completed the sentence (e.g. fail to pay the fine or fail to complete community service work) the record will remain with you until after the sentence has been completed. Section 119(2) of the Youth Criminal Justice Act (Canada) has all the criteria for removing the offence from your record.
If you are convicted as an adult offender prior to the expiry of the period of access of the youth record, the youth record becomes an adult record. The criteria for removing the offence from your record under the YCJA will no longer apply to your record.