What is the title for I am a student in freshman/sophomore/junior/senior college?

I am a student at undergraduate or postgraduate level.

请问“我是一名大一至大四的学生”用英语怎么说？

I am a student from the first to fourth year of college.

或者可以这样表达：

I am a student in the first to fourth year of college.

或者更正式地可以这样说：

I am a university student in the first to fourth year.