Gretchen Olson, who shared an introductory German class at Western Connecticut with Lanza, said Monday she also believed he was quiet because he was so young "in a class of 20-year-olds."
"We never really knew much about him," she said. "We said hi to him from time to time. He smiled sometimes."
Lanza was among a small group of 16-year-olds among the school's 5,000 undergraduates, Steinmetz said.
The Hartford Courant and The Wall Street Journal first reported Lanza's academic record at Western Connecticut State.
Steinmetz said Lanza took his last class in the summer of 2009 and didn't return.