They'll be fine. Sooner is better, but my son had to move last year with two AG kits pending, both from Midwest with pre-crushed grain. It was 6 months before he got settled enough in his new place to brew again, and the beer was fine. Note that this was grains in sealed plastic bags......
Now that I'm brewing AG, I order my grain uncrushed, and generally crush the day before brewday.
“Malt does more than Milton can / To justify God’s ways to man”
-A. E. Housman (1859–1936). A Shropshire Lad , 1896.