Valdez helped cover up her son's crime after sheriff's deputies say her son shot a 91-year-old in the face during a home invasion.
Valdez pleaded no contest to the charges in late August. Since she already served her time over the past two years, she will remain out of custody and on probation.
Prosecutor Jeff Dupras felt she deserved more time behind bars.
"I would have liked to have seen her get more quite frankly, because the underlying crime was so horrendous," said Dupras. "However, it's what the legislature has put to this crime and my job is to follow the law."
Investigators say in the days following the attempted murder. The suspect's mother hid her son and lied to deputies. She also provided an alibi for him and instructed another family member to get rid of evidence.
Leroy Falk represented Valdez. He says she had a compelling case.
"It was unfortunate," said Falk. "I think that she maybe should have taken it to trial because I don't think a jury would convict a mother helping her son. Even if the allegations are true."
Fresno County Sheriff's deputies say early Thanksgiving morning in 2011, 17-year-old Oscar Soto broke a window at the San Joaquin home where Marilyn Miller lives with her 91-year-old mom, Marcella.
Prosecutors say Soto terrorized the two before shooting the eldest woman in the cheek. Marcella survived the critical injury and according to the deputy district attorney, is doing well.
Falk says Valdez was in a difficult situation, no matter what choice she made.
"If you are a mother and you learn your son is accused of a crime like that and there's evidence there," said Falk. "You might get rid of it too. And I don't know if that's even a crime."
According to court records, Valdez was arrested and released from jail on bond before deputies arrested her again for intimidating witnesses.
Deputy District Attorney Jeff Dupras says Valdez went to great lengths to protect her son and he has little sympathy for her.
"She really encouraged him not to turn himself in," said Dupras. "And did conceal him at a certain point and when the police or sheriff came to talk to her, she did not cooperate."
A jury found Oscar Soto guilty of seven felony charges. He is set to be sentenced next month.