What are the changes in Pip's life up to the point where he declares his love for Estella to Herbert?Great Expectations by Charles Dickens

In Pip's life there are psychological as well as physical
changes effected before he confides in Herbert his love for Estella in Chapter XXX of
Great Expectations.

In Chapter I at
the graveyard, Pip is accosted by a strange gray man, a prisoner, for whom he later
steals and lies.   

Certainly his introduction
to Estella is responsible for many of Pip's
changes.

• When he is summoned to play with her at
  Satis House, Pip's state of mind undergoes conflict and alterations. Prior to his
  encounters with the child Estella, Pip is content on the forge with the fatherly love of
  Joe.  However, when he meets the "proud young lady," Pip is made aware of his being a
  "common labouring boy" who wears "coarse boots," and who is an object of ridicule rather
  than love and praise as he is with Joe
  Gargery.

Some time after his visit to Satis
House, Pip is apprenticed to Joe as a blacksmith, and Miss Havisham gives Pip
money.

Pip meets with a mysterious stranger who gives Pip
some money.  This monetary gift presages the greater gift of his "great expectations"
with Mr. Jaggers as the emissary on a Saturday night at the Three Jolly Bargemen after
Pip has become the apprentice for Joe. He informs Pip that he is to come into a great
deal of money and offers Joe money for Pip's papers of indenture.  But, Joe releases Pip
freely.  Pip is elated that his wishes have come true.

Pip
is fitted with suits and other gentlemenly attire prior to his departure for London
where he is to be educated and become a gentleman. He discovers "the stupendous power of
money." In his misdirection, when he returns home, Pip urges Biddy to help Joe to
improve in his manners and speech, which are
"backward."

When the hypocritical Uncle Pumblechook fawns
before Pip now that he is the possessor of money, Pip, in his new delusions of
grandeur, succumbs to his flattery and convinces himself "that he [Pumblechook] was a
sensible, practical, good-hearted, prime fellow."

On the
day that he is to leave for London, Pip, now too proud to be seen with Joe, tells him
that he will walk away alone.  But, as he rides in the coach, Pip does contemplate his
ingratitude.

Once in London, Pip meets with Mr. Jaggers who
informs him that he will "go wrong somehow."  Later, he meets Herbert, who changes Pip's
name to Handel and instructs him in table etiquette.

Pip
meets Bentley Drummle, the Spider, and Startop and Mr. Jaggers's housekeeper, Molly.  He
develops a rivalry with Drummle, who courts Estella.

When
Joe comes to London to visit, Pip is embarrassed for Herbert to see him.  He hurries Joe
away, and later feels ashamed, realizing that he has let his new wealth separates
them.

Pip visits Satis House and sees again Miss Havisham
and Estella. After his reunion with Estella, Pip
reflects,

I
though those were high and great emotions.  But I never thought there was anything low
and small in my keeping away from Joe, because I knew she would be contemptuous of him. 
It was but a day gone, and Joe had brought the tears into my eyes; that had soon dried,
God forgive me! soon
dried.

Clearly, Pip has
changed from the innocent, trusting, and loving boy who cherishes Joe and his life at
the forge, to a young man with many pretensions and faults.