My question involves a driver's license issued by the State of: Pennsylvania

I turn 21 tomorrow, Saturday January, 16th. My license expires Sunday January 17th. Tomorrow on my birthday I am in EMT class with the county during the entire time the DMV is open (8:30AM-4:00PM). Sunday & Monday the DMV is closed. I read that it is illegal to drive with an expired license. The state has me in a pickle. I don't want my new license to say Under 21 Till January 16th so that is why I did not do it yet... What do you advise? Not driving would a nuisance since I run overnight duty crew Monday into Tuesday at the fire company I belong to and college starts Tuesday. Is there some kind of grace period to this. I just don't feel like getting pulled over and screwed by the state which is essentially what this looks like could happen...

Please Advise