How old is old?

Today as I picked Jack up from school, he regaled me with the history of his preschool while we strolled the halls on our way to the exit.

"You know, this school is actually not that old," he explained.

"Well, how old is old?" I asked.

"Eh? I am four."

"I mean, you said 'old' so I just want to know, what does that mean? How many years?" I inquired.

He paused, mid-stride. "Well...is 50 old?" he asked.

"Sure," I said. "Pop-Pop is 50...ish."

"OK. Then this school is actually not Pop-Pop-old."

"Good to know," I said, as we continued on our tour.

"And someone actually threw up right here!" he exclaimed, gesturing to a small spot on the carpet.