I'd suggest telling your parents and other friends what you're doing. You don't have to go into detail about why you're quitting (although you will be asked!) but by getting it in the open it may help you get through these situations in the future because there will, unfortunately, be many more to come. For me it's one the biggest challenges of sober life, being around people who are drinking and being expected to drink, but getting it out in the open that you're quitting is the first step to making these situations easier in the long run.
Good luck!