Come on, kid, I'm not that old.
5 seconds sound clip from the Mars Attacks! (1996) movie soundboard.
You can hear this line at 00:26:09 in the Blu-ray version of the movie.
Quote context
[...]
(VEHICLE PASSING ON THE HIGHWAY)
- Grandma, I bet you never thought you'd live to see the Martians coming to Earth.
- Just think of all the crazy stuff you must have seen in your lifetime.
- I bet people were pretty scared when they invented the train.
- Come on, kid, I'm not that old.
- I want to see Slim. I want to see Slim... and Muffy and Richie.
- Grandma, I'm Richie. I know, Thomas.
- Richie was always the best one.
- Right now the president is talking to other world leaders.
[...]