That is not how those slashes should be used. First off:
- <orthography> (how you write it)
- /broad transcription in IPA/ (contains enough information that someone who knows the phonology of the language can figure it out)
- [narrow transcription in IPA] (contains enough information that even someone who doesn’t know anything about the language can figure out how to pronounce it)
So you’d want to write <mig> = [my].
Then, secondly, [y] is the sound of the danish <y>, or the German <ü>, for example. I assumed you wanted to ask “is the danish mig pronounced like the english my?”. For that you shouldn’t use those slashes, but rather the orthography marks or none at all, because anyone who knows IPA will get horribly confused.
<mig> is pronounced [mɑj], according to wiktionary, so to answer your question: yea, pretty much like the English <my>.