WWII timeline ETO - US perspective

Just thinking about how things progressed from Pearl Harbor onwards.
Is it fair to say that the US armed forces, especially the army, were
really just a skeleton force in December of 1941? So really, it took
a good solid year for mass production to really kick in and for the
Armed Forces to get fully equipped, trained, battle tested, etc.? If
that's so, then it's really more like Jan of 1943 before you have a
well equipped force, in its entirety. By January of 1945, the Battle
of the Bulge is over and most of the heavy fighting on the Western
front is over. So that's really just two solid years for the ETO.
I'm just ballparking things here, but I would be interested to hear if
this sounds about right.