well, this is one of the most full of sense sentence there, let's not complain !
I always hear ikke as ægget, then have to think about the sense of the sentence before translating! "You are the egg from Denmark" vs "You are not from Denmark"... well... it is duolingo, but IRL I'm guessing it is the second one.
The of I for you always gets on my nerves a bit. My first thought is either English I or 'in'.
A reminder her that "I" refers to many people, so you are are telling at least two people they are not from denmark. I think "You guys are not from Denmark" should also be an acceptable answer, as 'you guys' is the english version of "I".
I (capitalized) is the plural equivalent of "du", like "y'all", "you guys" etc. Note that 'i' is a preposition 'in', so it really is necessary to always capitalize the pronoun.
Du is singular, and I is either plural ('you guys') or formal ('you... sir/ma'am')
UPD: translating the sentence from English into Danish you can use both I or du and it will accept your answer. Translating vice versa you'll just use 'you' all the time, no matter what was originally meant.
You're right, I'm not from Denmark. What gave it away? Was it the fact that I only know ~500 words of Danish?
I suspect I might be hearing this a lot when I'm living there this year