It will always remain on your juvenile record, but when you turn 18 (it can vary depending on your state) it will be sealed to all but law enforcement and the courts.
All criminal convictions, felony and misdemeanor, stay on your record until you die. After a certain amount of time they no longer effect your insurance etc (if they were moving violations).
Unless the offense occurred prior to your 18th birthday, criminal records are a permanent party of your history. They are not like drivers license points and 'go away' after a certain length of time.