I am by nature an introvert.
Call me an introverted girl. (Call me an introvert.)
I am by nature an introverted girl/person.
第一句比较好,在西方我们不太习惯说 an introverted female/girl/woman,你是女孩/男孩对我们不是很重要,并且从你的(英文名)一般人会知道你的性别。
I am an introverted girl.
introvert=内向
I am a shy girl.
I'm a shy girl.
I am an introverted girl .