* He's ashamed: Ponyboy comes from a rough home environment with his brothers, and he feels embarrassed about the fights, neglect, and lack of stability he experiences. He might be afraid of being judged by Johnny.
* He doesn't want to burden Johnny: Johnny is already dealing with his own difficult circumstances, and Ponyboy doesn't want to add to his friend's worries by sharing his own problems.
* He's afraid of being misunderstood: Ponyboy fears that Johnny won't understand the struggles he faces at home, especially since Johnny seems to have a more supportive family life.
* He wants to maintain a positive image: Ponyboy wants to appear strong and independent, and he might feel like admitting his home life is a weakness.
It's important to remember that Ponyboy is a teenager who is trying to navigate a complex world. He's learning to deal with difficult emotions and relationships, and he's still trying to figure out his place in the world.