Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done...

Newer NM-b is smaller than the old TW NM but whenever I have seen EMT sleeves
the run was a single straight section with no bends so it is pretty easy to do.
You do have to ream the burrs off the EMT to avoid damage but you should really
be using a Romex to EMT connector on the end.