She is an introverted girl and always keeps to herself.

她是个内向的女孩，总是独来独往。

youdao

I am an introverted girl, not able to express myself openly.

我是一个内向的女孩，不善表达自己。

youdao

At that time, I was an introverted, shy little girl, dare not take the initiative to make friends with others, because I am timid around strangers.

那时，我还是个内向、腼腆的小女孩，不敢主动与别人交朋友，因为我怕生。

youdao