By AARON KATERSKY and EMILY SHAPIRO, ABC News(NEW YORK) — A teenager who pleaded guilty to robbery in the fatal stabbing of Barnard College student Tessa Majors is set to be sentenced on Monday. The teenager, now 14, was charged as a juvenile, as he was 13 at the time of the murder in December 2019.He is expected to be sentenced to a minimum of six months to a maximum of 18 months in a limited-security facility. He will get credit for the time served since his arrest.Majors, 18, was stabbed to death on Dec. 11 in upper Manhattan’s Morningside Park, just off the campus of Columbia University, as three teenagers tried to rob her. Manhattan District Attorney Cy Vance said Majors’ last words were “Help me! I’m being robbed.” The other two teenage boys arrested, Rashaun Weaver and Luchiano Lewis, were both 14 at the time and were charged as adults.Weaver is accused of fatally stabbing Majors as Lewis allegedly held her in a headlock. Their trials on murder and robbery charges are pending. Both have pleaded not guilty. Lewis’ attorney declined to comment to ABC News on Monday. Weaver’s attorney could not immediately be reached for comment.Copyright © 2020, ABC Audio. All rights reserved.