He was 150! Not 100.
4 seconds sound clip from the Finding Nemo movie soundboard.
You can hear this line at 01:30:43 in the Blu-ray version of the movie.
Quote context
[...]
- Oh, no, no, no. I'm so sorry, Nemo.
- What?
- Sea turtles. I met one. And he was 150 years old.
- 150?
- Yep.
- 'Cause Sandy Plankton said they only lived to be 100.
- Sandy Plankton? Do you think I would cross the ocean and not know as much as Sandy Plankton?
- Who is this Sandy Plankton that knows everything wrong?
- Time for school! Time for school! Get up! Let's go! Let's go!
[...]