Centennial, Colorado (CNN)After months of intensive questioning, a jury has finally been picked for the trial of Colorado movie theater massacre suspect James Holmes. Twelve jurors and twelve alternates are on the list. The group includes 19 women and five men. It's almost entirely white and mostly middle-aged. It's a key step in the case, and it's been a long time coming. Jury selection started in January with 9,000 potential jurors. But the legal wrangling is the case is just revving up. Holmes' defense attorneys asked for a change of venue after the jury was seated Tuesday. The judge denied their request, noting that a jury had already been seated. Opening statements in the trial are scheduled to begin on April 27. Holmes is accused of killing 12 people and injuring 70 others when he allegedly opened fire inside a packed theater during the midnight showing of "The Dark Knight Rises" on July 20, 2012. The one-time neuroscience doctoral student faces 165 counts, including murder and attempted murder charges. Now 27, he has pleaded not guilty by reason of insanity. If convicted of the most serious charges, he could face a death sentence. Wearing a gray dress shirt and tan slacks, Holmes sat quietly in court on Tuesday, looking relaxed and leaning back in his chair for much of the day as lawyers made their picks from the jury pool. He looked down often, but smiled occasionally, such as when the judge made a joke about a juror needing to share his Cheetos and when the district attorney accidentally addressed a male juror as a "Miss." Even though he looked calm, defense lawyer Tamara Brady started her question and answer session with jurors Tuesday by expression concerns about Holmes getting a fair and impartial trial, saying "I'm nervous" and "my client is nervous." District Attorney George Brauchler warned jurors to brace themselves. Tuesday's court session, he said, was the lawyers' last chance to find out if there is "any reason you shouldn't be one of the 24 to sit through the four to five months of a horrible roller coaster through the worst haunted house you can imagine." CNN's Ana Cabrera and Sara Weisfeldt reported from Centennial City. CNN's Catherine E. Shoichet reported from Atlanta. CNN's Michael Martinez contributed to this report.
In the murder trial of James Holmes, 12 jurors and 12 alternates have been selected .
The mostly middle-aged group includes 19 women and five men .
Jury selection started in January; opening statements are scheduled to begin on April 27 .