yeah parents are always concerned with not even their child, but how other kids will effect their own kid. thats why you see parents sometimes trrying to influence their kids to kick it with THIS kid, or chose their friends somehow for them subliminally. im 20, and ive been dealin with the drinking thing for a lot longer than you prolly. parents still dont care, they see me coming down the home stretch and they're like, ha ya you're 21 in our eyes, but when you get in trouble, you're still 20... and fucked. so i understand / appreciate the concern from that corner of the room. but if you're in highschool n drinking, higher chance you're gonna get in trouble, you're on the police's radar when you're in highschool man they're lookin for you trust me. college even the same way, moreso. because theres people that got away with it in highschool that do it even more frequently in college because of that, theres the people that share my mind set, that A) im 20 and can deal with my own shit 2) im 20 and think im 21. C) i just would drink beer anyways. haha funny ass story right here that might work for your mom if you know how to pick your spots.
i'm drinking with my homies in a nice house basement, parents are home but it's just late at night after a lacrosse game in highschool. nice area, no way to even remotely get in trouble doing what were doing. and his mom comes downstairs and we're all just watching a movie drinking what seemed like a beer each or maybe two including an empty a piece on the table because the other 30 empties were in the garbage.... LOL.... and his mom comes down and she starts flipping a shit, much of the same reacting i bet you had to experience cept in an enclosed space where she could easily start backhanding you, SO I DIDNT HAVE TO DEAL WITH THAT part... but she was freakin, cuz we were like 18 and she was a pushover mom and rich and didnt have anything else to do but put the hammer down. she even like, paused for a few seconds like she wasnt even caring... i was stoked, then she starts trippin on my friend, his mom. and his argument was basically. MOM, IT COULD BE A LOT WORSE TRUST ME, WE COULD BE DRIVING AROUND RIGHT NOW AND DOING GOD KNOWS WHAT FOR ALL YOU KNOW. NO, WERE RIGHT HERE IN THE BASEMENT, SITTING, WATCHING A MOVIE. IT COULD BE A LOT WORSE MOM, WE COULD BE DEAD... (and i think at that point i chimed in and said "yeah mrs. sulzbacher" then i got told to be quiet, but i think that statement really calmed her down, because all she said was ok henry we'll talk in the morning. and so she went upstairs and we went back to drinking and he dealt minorly with it the next morning.
tell your mom you promise promise promise, say that shit. that you'll never drink and drive, EVEr, period. case and point. bam. good luck to you man.