Misdemenor's when under 18: do they drop once you turn 18?

I work with lots of people who have security clearances out the wazoo and many did much worse than that in their youth. I wouldn't sweat it too much.

The answer is: it depends on the state.  In Florida all criminal traffic offenses (which DUI is ) whether committed as a juvenile are heard in adult court.   Additionally, in Florida criminal traffic offenses for which you were convicted stay on your drivers record for life.  Interestingly, if you have a DUI from another State and move to Florida and get a Florida Drivers License, your out of state drivers record can be merged onto your Florida DL.

Simplest thing to do is go to the clerk of court in your home town and ask for an official print out of your drivers license record, there will be a small fee,(Where I am the fee is like $10).  You can then see if the conviction is on your DL.  If it is, you may be able to move to either seal or expunge the conviction.  The requirements and eligibility for that vary from state to state.

Oh and DUI's do show up on NCIC's, which is the criminal history report that is run for most employers and all government agencies.   There is no time frame for these convictions being removed from NCIC, in fact juvenile convictions show up.  The only way to get them removed from NCIC is to have the conviction sealed or expunged.

agreed, the OP never said this was a motor-vehicle related offense, so I don't know where ASA got that

Sorry, mis read the OP.  To address the minor in consumption of alcohol (in Florida we have possession of alcohol by person under 21)  the short answer is even juvenile arrests and findings of delinquency stay on ones NCIC unless sealed or expunged.  Again, the question becomes whether a potential employer has access to the NCIC, some do, some dont'.  In Florida findings of guilt in a juvenile proceeding are not criminal convictions, they are findings of delinquency.  Thus, if asked in Florida if one has ever been convicted of a crime, and all the person has is a juvenile record they can truthfully answer in the negative.

I'd still check my DL, in Florida possession of alcohol by minor carries a mandatory DL suspension (6months for first offense).  The dirty little secret is that even after 6 months if you don't go to DHSMV and pay a reinstatment fee your license is still in a revocation status.  This may not apply in whatever state the OP was at the time.   But most states have similar type punishments for underage drinking.   

I believe that you can have your own NCIC run.  I believe our sheriff's department offers this service at a nominal fee. Check with your local law enforcement agency to see if they offer this.  You could check your criminal history to determine if your conviction appears.  If it does and you feel strongly about it you can always petiton to have the conviction expunged or sealed, depending on the requirements of your state.

This of course assumes that MIC in the state of the OP is a criminal offense, it might not be.  The OP said he was "cited" for MIC, this may be a civil offense, if that's the case it won't show up on a criminal history as it isn't a criminal violation of the law.

Here's what you should do:

1. Check your driving and criminal record in Idaho. You need to be armed with facts about what anyone could discover about your background.
2. If you find that you do have a record (driving or otherwise), you can pay an attorney to get the record expunged. I would go for the expungement option rather than sealing the record. Expungement means any future employment screening will not reveal a record at all because it should no longer exist.
3. After the expungement is done, check your records again. You need to make sure the attorney did his job properly (they don't always do it right).

Be aware that if a prospective employer discovers you have a record, you can lose a job offer if you falsely claim to have never been arrested or charged with a crime. It is better to answer honestly - that you were detained and cited when you were a minor. Most employers will not penalize you for that, but they will penalize you for lying about it. I have seen people lose a job offer not because they were arrested, but because they lied on their application. I've also seen people surprised that an arrest record was found because they thought their records had been expunged (and the job offer was rescinded as a result of not disclosing the arrest).

Also, you do not need to volunteer this information to a hiring manager. The only persons who should see this information on your application for employment are human resources people and they should not be disclosing the information to anyone outside HR.

The issue of expungment vs sealing isn't as easy as this.  The end goal is always expungment however, in many states(FLa. for one) expungment is only an option if the charges were never filed on or once filed the charges were dismissed prior to a dispositional hearing.  If not then you must petition to have your record sealed.  Once your record has been sealed for 10 years you can then get the sealed record expunged.

Addtionally arrests, or convictions for certain offenses cannot be sealed or expunged regardless of the disposition.  Certain sex offenses, crimes against children, crimes against the elderly for example.  Also, you only get one bite at the apple, you can only seal/expunge once in your lifetime.