Sounds to me like she was potentially jealous that you knew who you were, didn’t hide your thoughts and feelings, and her being insecure herself interpreted that as you acting like you were someone you aren’t. Your description comes off a lot like she was projecting. She probably has a lot of insecurities and feels like, herself in your shoes, she would have to act arrogant and haughty in order to mask her own insecurities to present herself similarly to how you present yourself.