I'm not 100% sure, but I would suggest that you dry it first. The trichomes will fall off the trim easier, plus the chlorophyl and whatnot will mostly have drained...you don't want it making your butter taste bad.

There are quick ways of drying it, just don't go too hot and burn the THC. I like to use a dehydrator on 95F. It doesn't get hot, and the airflow shortens my drying time from 4-6 days to 24 hours. I only do this if I have to; I usually let it properly dry.