那个女孩和我的成绩等级一样用英语怎么说

可以用 "She has the same grade level as me." 来表达这个意思。

其中 "grade level" 是指学生在学校中的年级水平，例如小学、初中或高中。

例句：

She's in the same grade level as me, so we're in most of the same classes.
I found out that my new neighbor has the same grade level as me.
He's a year older than me, but we have the same grade level because he was held back a year.

中文翻译：

她和我同年级，所以我们上了大部分相同的课。
我发现我的新邻居和我同年级。
他比我大一岁，但我们同年级，因为他被退学了一年。