I chose: Я вегетаріанець, отже не їм м'ясо (without the second я) and got it wrong. I was told by a Ukrainian native that a second Я in a sentence is not necessary because the verb, which in this case їм implies the Я.
The course does not include sentences with omitted pronouns. They are normally dropped in colloquial informal contexts.
Are you sure you didn't get it wrong because you didn't also choose the second correct option?
Я вегетаріанка, отже я не їм м’ясо.
Can м'ясо be genitative here (as it is negated)?