I mean you got the right to know what you're being harassed about
It's always best to cooperate, especially if you know you have done nothing wrong.
You got to learn how to talk shyt without showing attitude or disrespecting. If they asked what are you doing, you should've just said you're walking.
Like I said before, if they ask for ID give it to them. You don't have to stop smoking or even sweat it, you're in your legal right to smoke cigarettes.
Anyway, they gonna probably try to get you for resisting arrest.. Thing is they have to let you know what you're being arrested for. If they took you in they should've gave you a breathalyzer at the jail, and if you didn't test positive then they would've looked dumb.
And I'm not even sure if under age drinking is even a major crime. Selling to a minor should be worse