I would leave them alone for a while yet, as long as the tops remain somewhat plump and green. I'm growing shallots again this year, after many years of not, so can't remember if I treated them any different than onions.

Some years I get lazy and leave my onions in the ground until just before frost. They seems to keep just fine, just that you can't store them nicely braided since the tops are too flimsy by then.