Freshman Democratic Rep. Alexandria Ocasio-Cortez questioned 2020 front-runner Joe Biden’s “capacity” to be president, citing his performance in the first presidential primary debate.

“I think Joe Biden, his performance on the stage kind of raised some questions with respect to that. But I don’t want to say just because someone is 79, they can’t or shouldn’t run for president,” Ocasio-Cortez said in an interview with The New Yorker Radio Hour published Tuesday.