What are some events in The Outsiders that demonstrate that Ponyboy was struggling with his identity, but essentially remained his true self?

An example of an event when Pony struggled with his identity was when Pony and Johnny are at the movies and run into two Soc girls, Cherry and Marcia. Pony and Johnny are with two other greasers, Two-bit and Dallas. Dallas behaves crudely toward the girls, and Cherry asks Pony why he would hang out with someone like him.

Cherry was looking at me. "What's a nice, smart kid like you running around with trash like that for?"

I felt myself stiffen. "I'm a grease, same as Dally. He's my buddy." (Chapter 2)

Pony defends Dally to Cherry because he is a greaser. Even though Pony is different than other greasers, he still considers himself a greaser. Greasers stand up for each other. Cherry acknowledges Pony is different. This is why she asks him why he would hang out with Dallas.

The conversations with Cherry were an interesting experience for Pony. Pony begins to look at things from Cherry’s perspective because she tells him some things about being a Soc he had never really considered. She tells him these things because she thinks he is more sensitive and reflective than other greasers.

"I'll tell you something, Ponyboy, and it may come as a surprise. We have troubles you've never even heard of. You want to know something?" She looked me straight in the eye. "Things are rough all over." (Ch. 2) 

Pony knows Socs usually have violent altercations with the greasers, but he is willing to accept they have problems, too. He knows not all Socs are alike, and is willing to see things from their point of view.  

Pony finds himself in another new situation after the fight where Johnny kills Bob, the Soc, which causes Pony and Johnny to need to go on the run. Pony finds it difficult to believe Bob is really dead, and that Johnny really killed him. That is the real situation, though. Johnny and Pony end up hiding in a church outside of town because Pony was with Johnny when he killed Bob, and he is afraid he is going to be blamed, too.

Even through the incident at the church, the rumble to follow, and Johnny's death, Pony remains true to himself. He wants to fight in the rumble because he wants to support his friends, but the other greasers know Pony is not a fighter. Johnny tells him to stay gold before he dies. Everyone knows Pony was made for another kind of life.