Barbara Sheehan was convicted of gun possession for using her husband's weapon to shoot him 11 times.
Sheehan claimed she shot him after suffering decades of abuse.
She expects to be formally sentenced next month, but the judge said she must turn herself in to begin serving her time.
Sheehan surrendered around 9:30 a.m. She was handcuffed and led away, but her lawyer continues to argue for her release.
Sheehan's attorney says he was never allowed to put on an expert witness who would have testified that she was a battered woman living in mortal fear of her life. The judge's decision to block that witness was, in the attorney's words, a violation of Sheehan's rights.