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.