You generally have between a week and 10 days to get them out. Males release their pollen reletively quickly, and they do it repeatedly. If you're uncertain whether or not you're looking at a boy or girl, it's probably a dude. Female plants are very distinctive, look for a little calyx with two little pistils (hairs) coming ot of it. The calyxs will for first at the base of leaves, look for them. Dudes will grow balls that hang in bunches, pretty easy to spot.

Peas out