He had two past convictions for assaults at the mall, both in 2015, and had been banned from the property at one point. Court records showed that Aranda had been ordered to undergo psychological evaluation or treatment after those attacks.
His attorney, Paul Sellers, previously said Aranda had been in mental health court in the past. But he said after Tuesday's hearing that Aranda was mentally competent enough to proceed in the attempted murder case.
"He is competent, clearly. I wouldn't be able to go forward with the plea if he wasn't competent," Sellers said.
He added that it was "absolutely, 100 per cent" Aranda's decision to plead guilty.
"He went into the courtroom and accepted full responsibility," Sellers said. Barring "something unbelievably unusual," Aranda will be out of prison in about 12 years, he said.
Aranda spoke quietly during the hearing while giving yes-or-no answers to questions aimed at making sure he understood what he was admitting.
The child plunged almost 12m and suffered head trauma and multiple broken bones. Authorities have not released the boy's name and say his family requested privacy. His family released a statement in late April saying the boy was alert and no longer in critical condition. On Monday, the family said he has continued to heal.
- AP