Start working at a bar as a waitress. Learn the trick and the drinks of the trade and as time goes by you’ll be making drinks like the rest of them. Then perhaps the bar you once worked at as a waitress will hire you as a bartender, then you can leave them once ready and get a good reference from them.

You should actually get a job as a barback, not a server.
Make sure you express interest in wanting to bartend and be willing to pick up any shift (even those crappy Monday lunches) and be on call for any bartender that can’t make it in.

There are websites that can teach you how to bartend.
Don’t fret about not going to school. Most folks I know that are bartenders didn’t go to school and the folks that went to school to bartend aren’t bartenders.