进入高三的英文表达有多种方式，以下是一些常见的表达：

We are about to enter into the third year of school.

We are going to enter senior three.

I will become a student in senior three.

Enter senior three.

We are in the process of entering senior high school English.

这些表达都可以准确地传达“进入高三”的意思，可以根据具体语境选择合适的表达方式。