Why is petra the wrong friend to have for ender?

Petra is often seen as the wrong friend for Ender because her focus on personal ambition and competition can distract him from his goals. While she is skilled and driven, her approach may not align with Ender's more strategic and empathetic nature. Additionally, her tendency to prioritize her own success could create tension in their relationship, making it harder for Ender to trust her fully in the high-stakes environment of Battle School.