In my experience, woodshop (also called, "Wood Working" or "Tech Ed") takes place in Middle School and High School. I am going to assume that same rules apply for the SpongeBob Universe. The wood shop evidence is presented when Patrick asks, "Who made a spatula out of toothpicks in wood shop?" in Help Wanted.
We know that children are in the same grade (or at least about the same grade) because Pearl was in High School when she was 16 as presented in Whale of a Birthday.
Using these two pieces of evidence, we can say that, because SpongeBob was born in 1986, the series begins in 1998, 1999, 2000, 2001, 2002, 2003, or 2004.
However, because Christmas Who? premieres in 2000 and Patchy presents SpongeBob's first Christmas as being in the past, we know that it must take place in 1998 or 1999. We know that SpongeBob has his job in that episode.
Using math from the Employee of the Month awards in the first movie I know that the series either begins in December or January. If we use the majority of the American education, we can assume that kids start in September (more evidence of this is presented in Krabby Land with the kids leaving school in June.) Therefore, it would have to take place after September 1998.
If all the Employee of the Month awards are presented at the end of the month like in Employee of the Month, then January 1999 is not a possibility.
With all this evidence, we can say that SpongeBob SquarePants begins in December 1998 or December 1999.
With this evidence, the first movie takes place in March 2030 or 2031.