Can you help me with this?
Are both sentences correct?
It is me who am your teacher
Or
It is I who am your teacher
Only the latter is correct. It "follows the general rules for relative clauses, with the relative pronoun who being construed as 1st person singular by virtue of its anaphoric relation to I" (Huddleston & Pullum, 2002: p. 507).
If you want to use is, the pronoun has to be accusative. This is the case of 3rd person override in cleft relatives (ibid.). And as Michael Harvey mentioned in the comment, this is more common in Present-Day English:
It is me who is your teacher
I is
or me is
? Well, I would say neither. But if we use a different pronoun, it would be he is
(the subjective case) not him is
(the objective case). Despite both of those tests, it is me who is
(the objective case) is being used here. I actually suspect this is like the answer to Who is at the door? Strictly speaking, it should be It is I, but pragmatically, in modern English, it's It is me.
Commented
Jul 27, 2020 at 22:00
I am
orme am
?.It is I who am your teacher
, but this is very old fashioned.It is me who is your teacher
is more likely.