Does anyone have any examples of epiphanies in literature?

This is a great question, though I see you're in 9th grade
and some of my best examples may be from things you haven't yet read.  An epiphany, of
course, is a moment of awakening, of realization, which generally changes a person's
motives, outlook, actions, and/or thinking.  It may be triggered by something big or
small, and it often happens in private rather than in
public.

In Romeo and Juliet, the
feuding families have a sort of epiphany when they realize their children have died for
their foolish enmity.  The Capulets and the Montagues are sworn enemies until they step
into the tomb and see what their hate has caused.  At that moment, they each vow to
honor the other's fallen child in some public way.

In
Oedipus, King Oediupus has an epiphany when he suddenly realizes he
is the one who has brought a curse upon his town by inadvertently killing his father and
marrying his mother.  When he realizes it is he who is the curse, he immediately blinds
himself because he can no longer bear to see his own face after the horrors he has
committed.

In The Crucible, John
Proctor has an epiphany when he has to either sign his name to a lie or die.  He
believes he is already a sinner of the worst sort, so he signs his name to the false
confession.  Almost as soon as he does, he has an epiphany in which he understands that
God will forgive his sins and he will die as a forgiven man.  He then tears up his false
confession, thus sealing his own fate--death on this earth but eternity in
Heaven.

In Animal Farm, Benjamin the
donkey is a rather quiet animal, totally dedicated to his friend Boxer the horse.  Boxer
is symbolic of the working man in this allegory, and Benjamin represents the academic or
scholarly people in the country.  When Boxer has literally been worked to death, the
animals are told he is being taken away to the hospital.  Instead, though, the dying
horse is being taken to the knacker's to be butchered for his parts.  Benjamin can read,
and when he sees the name on the side of the cart, he has his epiphany.  He understands
they have all been lied to, and that if Boxer leaves the farm he will never return. 
Benjamin raises the alarm and rallies the animals, but his moment of understanding comes
too late. 

There are lots and lots of similar examples
throughout literature, but I'm hesitant to give you too many from things I'm guessing
you haven't read yet.  Hope this was helpful to get you started thinking about
epiphanies.  I'm confident that, looking back at other things you've read, you'll find
even more examples.