Lindsay Lohan -- Screw All You Doubters ... I'm Gonna Finish My Community Service

Lindsay Lohan is about to pull off something we were prepared to bet money against. It looks like she'll complete all of her community service by Thursday's deadline ... but just barely.

As we reported, Lindsay went to Brooklyn earlier this month to beat the court deadline, and it seemed like an impossible task. She had to complete 115 hours, which meant 8 hours a day, every single day.

Going into Memorial Day weekend, we're told she only had 26 hours left to complete. Lindsay spent the weekend working at a New York LGBT Youth Center and was back on the grind Tuesday at a Brooklyn child service center.

Sources at the center tell us Lilo did 8 hours Tuesday and will log in another 8 today ... combine that with the weekend work and she'll cross the finish line.

There's a lot at stake. We're told the judge is prepared to end her criminal case on Thursday one way or the other -- either she completes community service and is taken off probation or she goes to jail.

Lindsay's lawyer, Shawn Holley, will be in court Thursday to deliver the judge the good news.

Way to go, Lilo.