At the beginning of the film, Amy (Daughter) is going off to her freshman year of college. Adam (Baby) is two years old at the time implying that he was born shortly after the first film ended.

However, during the TV show between 1997-2000, one of the last episodes ends with Diane announcing that she is pregnant with Adam, and shortly after Amy is going to leave for college.

The problem here is that with the TV show Amy has to be 14 in the first film and Nick is 10. The problem with this is that Amy has her learners permit which for most of the country you get at 16. In the Trilogy Amy is 15 and Nick is 10.

Unless Wayne uses the time hopper (See the TV show) on Diane to speed up her pregnency then something is wrong with the timing of the show/film.