Stakes High for Amanda Knox When She Takes the Stand

Amanda Knox is about to face what she could have never imagined.

If life had gone according to plan, Knox would graduate from the University of Washington in Seattle this weekend. Instead, she will take the witness stand to defend herself in an Italian courtroom where she has been on trial since January, charged with murder.

College graduation is just one of the milestones Knox has missed while held in a prison in Perugia, Italy, for the past 18 months. Knox had dreamed of spending her junior year abroad in this medieval Italian town in the Umbrian hillside. But not long after she arrived, Knox went from being a sweet-faced coed to what newspapers described as an accused killer with "icy blue eyes."

VIDEO: Amanda Knox defends herself in Italian at her trial.Play

Knox, 21, and her former boyfriend Raffaele Sollecito, 25, are accused of sexually assaulting and murdering Knox's British roommate, Meredith Kercher, 21.

Kercher was found stabbed and strangled to death in her room in the house she shared with Knox and two other women, Nov. 2, 2007. A third person, Rudy Guede, has already been convicted and sentenced to 30 years in prison for his role in the murder.

VIDEO: Knoxs Dad: Trial Has Taken Toll.Play

Knox and Sollecito, on trial together, maintain their innocence and claim they were together at Sollecito's apartment the night of the murder.

After five months of testimony in which witnesses have often portrayed Knox as an inappropriately behaved and bizarre young woman, in what her father, Curt Knox, has called a "character assassination," the defense will have its chance to show the jury that Knox is innocent. She begins her defense and takes the stand for questioning June 12.

Knox may begin in her testimony in English but will likely speak mostly in Italian, her father told ABC News. She planned to make a last-minute decision on the stand, he said.

Amanda Knox's Father: 'She Knows She's Innocent'

The decision to take the stand was Knox's and that of her lawyers. Sollecito will not be questioned.

Knox's decision to take the stand is a "no brainer," according to Los Angeles defense attorney Roy Black who has been following the case closely.

"If she doesn't get up there and put on a good performance, have a good explanation, I think there's a very good chance she's going to be convicted," he told "Good Morning America."

One thing Knox has going for her, Black said, was the prosecution's "weak" theory that the killing was the result of Kercher's refusal to participate in a sex game.

"I think that's the weakest part of the case for them. They say some type of sex orgy was planned and the victim didn't want to go along with it. So she was killed because of that. I don't find that particularly convincing," Black said.

Black suggested Knox should blame the killing on Guede who has already been convicted of taking part in the murder and whose fingerprints and DNA are already established at the crime scene.

Xavier Amador, a Columbia University clinical psychology professor who frequently consults on criminal trials, suggested that Knox has a unique problem with the jury in Perugia.

He noted that the Italian media has written luridly about Knox's behavior after her arrest and during the trial and that Italian jurors are not screened for biases or preconceived notions, and not told to avoid reading about the case as they would be in the U.S.

"I would have a difficult time trusting that jurors with long breaks between hearings and, and evidentiary hearings where they have access to the media, especially in a high profile case, are not reading news accounts," Amador told ABC News.

The first questions will come from her lawyers, but then Knox can be cross-examined by the prosecution, lawyers for the civil plaintiffs and the judge, Giancarlo Massei.

She can choose to interrupt the questioning at any time, or choose to answer certain questions and not others, but if one takes the stand, it is assumed one plans to answer the questions.

Knox's father, who will be in court to support his daughter, says she is eager to take the stand and explains, "Some people may consider [taking the stand] a risk. It's not a risk because she is 100 percent innocent. She knows that and wants to tell the truth."

Amanda Knox's family members says they worry about media portrayal of their daughter as a calculating and conniving killer, dubbed the "angel face with icy blue eyes." For a year and a half, the international press has painted Knox as a person her father says is "180 degrees from who she really is."

He says that with his daughter on the stand, speaking in her own words, "I think people are going to see that she's a real human being, not the monster she has been pictured and painted as."

But not only is Knox up against often harsh and negative press, she also faces the Italian justice system, which has notable differences from the American judicial system.

Differences in Italian and American Judicial Systems

Deciding Knox's fate are two judges and six jurors. Italian jurors, who, in this trial, are citizens of Perugia, are not screened for biases or preconceived notions perhaps gleaned from the press. They hear testimony on average only two days per week.

It's a dangerous delay for Knox during which the juror's opinion could be swayed by media reports, Black said.

"Letting the jurors read all the press -- the tabloid press has been rough on her," he said.

In Italy, defendants are allowed to and even expected to lie. While witnesses have to swear to tell the truth, defendants do not. It is assumed that if they are defending themselves, they might not tell the whole truth, and will not be charged with perjury if they don't.

To decide a verdict, both the judges and jury vote and only a majority vote is needed. In the United States, a jury vote must be unanimous. Both the defense and prosecution plan to appeal the verdict.

Knox Trial Expected to Last Until Fall

With the court taking nearly a two-month recess for the Italian holiday, a verdict is not expected until the fall. If convicted, Knox and Sollecito face life in prison.

Knox's family refuses to accept the worst case scenario but understand its nightmare will not likely end anytime soon.

Curt Knox reflects in a quivering voice, "We stay focused on Amanda and making sure that that light is there for her. We just work through it, we just have to. We are not going to leave an innocent daughter in a foreign prison."