给你建议的写法如下:
“Strictly speaking, I am not a (qualified) teacher, because I did not/have not...."
(直译就是:严格来说,我不是一个(合资格的) 老师,因为我没......") ,
又可以说成:"I am not a well qualified teacher, because I did not/have not" (我不是一个很合乎资格的 老师,因为我没......")
后面的 "did not" 或者 "have not" 就看之后的说话和意思再继续写下去。
希望对你有用。