If a Juvenile steals something and then is arrested for the theft the Juvenile will usually be charged for Peti Theft and be charged with a misdemeanor.
The misdemeanor charge will usually get the Juvenile in Jail for at least 3 months because the charge is usually charged as a misdemeanor of the second degree which in most states is punishable by a maximum of a $500 fine, and/or no more than 60 days in Juvenile Detention.
If the minor commits a second offense then they may get 6 months in jail and possibly another $500.00 or even $1,000.00 fine.
If they steal again then the minor may go to jail for up to a year or more.
It's never wise to steal anything and the higher the value of the theft of the item then the more jail time the minor will get.
They might then charge the minor as an adult and send them to prison for 5 or 10 years especially if the theft of the item or whatever it is was worth more than $5,000.00 or if the minor commits the theft crime a 3rd time.