What are the chances of NOT getting my license suspended for a year or at all with a charge of 23136vc ?

Near zero. The same percentage as the State's tolerance for under age drinking. Under 21 with a conviction is an automatic suspension of your license. Period, end of story. As to your background check, that's a heavy hit because it will follow you for years to come. Your only chance is with an attorney who will attack the stop, the instrument, the officers training and observation and the actual reading on the instrument looking for something, anything that may cast doubt into the minds of a juror. Again, good luck.

If you lose the DMV hearing you will lose your license for a year. Court can grant a critical need to drive per VC 13202.5. The DMV can, too, via a granted critical need to drive application. Whether it is on your record depends if filed as misdemeanor or an infraction, as a less than a 0.05 may only result in an infraction charge of VC 23136, which is what you cited. Hire a lawyer. It's advisable.

If your attorney can win the DMV hearing and avoid conviction at court (if there is a criminal matter filed. In Los Angeles, I have found that the court leaves it up to the DMV to handle these matters when the BAC level is below .04). It is possible to win these matters. The PAS device results need to be challenged (and several ways to do that). Hire an attorney who is familiar with how to fight these cases. Feel free to contact me if you would like to discuss further. In the event there is a license suspension, you can apply for a critical needs license. An attorney can assist you in that matter as well to increase the chances of getting it granted.