Can I have an arrest sealed that happened 17 years ago and do I need to come back to the state where it happened to do it?

It depends on the laws of the state where it occurred. You need to consult a lawyer who practices in the city or county where it happened. Your attorney can tell you whether it's possible to get it sealed. Most likely, if it's possible to get the arrest sealed or expunged, there will be a hearing and you would have to attend the hearing with your attorney. In Missouri, you can not get the record of an arrest expunged (removed) from your criminal record unless you were arrested based on false information and no charges were filed.

If this was an adult matter, it would be extremely difficult to seal the arrest record at this point. What may be possible, however, is to file a 17B motion to reduce the felony charge to a misdemeanor, and a 1203.4 petition to have the conviction "dismissed" or "expunged". Contact some attorneys who practice in the county where the case took place. Most offer free consultations and will help you better understand your options and the likelihood of success.