If you're just serious about something... about quitting drinking alcohol and just living a respectable life, they will respect it. If they can't respect it, they aren't your real friends. When it comes to some chick, why would not drinking come off as corny to them? Just say nah babygirl I'm cool. I don't drink.
If you're just getting off alcohol, it's best not to be in environments that encourage alcohol consumption until you're sound enough to where you don't get that urge.