Does Callie illustrate all the emotional problems that a person in real life would have in Middlesex?The author did not interview or meet with...

My first thought is that rather than trying to define her
experience as "accurate," you should focus on whether it is "authentic."  Keep in mind
that no two individual's stories would be identical, and when it comes to portraying
mood and emotion, there is no such thing as technically
correct.

As far as the authenticity of Callie's experience
goes, I would argue that yes, Eugenides does present an authentic characterization of
his main character.

To look at the authenticity of Callie's
experience in three overall points, I might encourage you to think chronologically. 
First, look at her childhood.

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I was brought up as a girl and had no doubts
about this.  My mother bathed me and taught me how to clean myself...instructions in
feminine hygiene were rudimentary at best...All was shrouded in a zone of privacy and
fragility. (226)

As a child,
with no visible differences between herself and other children, Callie accepts what she
is because that is what she is taught.  This is very normal behavior for any
child.

But look at Callie as an adolescent and the feelings
of fear and wonder she experiences when she doesn't hit puberty at the same time as her
peers.  Think too, how this confusion is heightened when she is not experiencing the
normal effects of female puberty.  Then, when she begins to have
her first crush on someone, and it is a girl (the "Object of Desire"), she hides it. 
While engaged in her first sexual encounter with a boy she
admits:

He was
rubbing my overalls, but I was no longer in them exactly.  My focus on the Object was
too intense. (374)

She
imagines herself inside the body of the boy who is with the Object of Desire, rather
than inside her own body.  This emotional detachment from herself is typical response of
someone who is having a sexual encounter at a very young age, and is not ready to admit
her true feelings to anyone, almost not even
herself.

Finally, look at Cal as a grown man.  His
relationships with women are difficult.  He admits to taking things very slowly.  He
admits to ending relationships just before things become sexual.  He is still nervous
and unsure of himself as a sexual being, and this naturally affects his
relationships.

If you look at the entire book as a whole,
understand that it is Cal's (Callie's) record of self discovery, which must go back to
two generations before her.  The simple fact that s/he feels it is necessary to even
tell her story shows that her emotions and acceptance of such an
unnatural and difficult life are authentic.