Is it ok to start questioning my gender identity because of external reasons?

Questioning your identity is always valid if it feels like the right thing to do, whatever the reason. However, I'm not sure what you mean by "external reasons", but in the end what truly defines your gender identity is something completely internal. It's how you feel, how you see and perceive yourself. External reasons can be misleading sometimes, since arbitrary social constructs can lead people to believe that something is "masculine" or "feminine" without a real reason. For example, there's no reason why a woman should wear certain things and a man shouldn't, because a person who identifies as a man or a woman is still a man or a woman, regardless of their style, preferences, behavior. It's all about how you feel.