I was in juvenile detention center for fighting?

Usually (not always) any indiscretion you have while a juvenile does not follow you into adult hood. Many courts seal juvenile records so they don't have an impact on the person when they become an adult. My assessment of the situation would be that you won't have any problem with the law since you were released on probation and it has been six years. If you still feel curious and vulnerable by this situation i would suggest you contact an attorney who can then check your records to see if there are any wants or warrants. Good luck and congratulations for staying out of trouble.