the bed we got finn has 18 months listed as the youngest age recommendation, though of course you can use it sooner. i think 2 1/2 is probably the average age for making the switch though. it's really up to you and jenny!
finn's been getting out of his crib but he's never made a sound when he does it, so i don't know how he's getting out so quietly but he's not falling and hurting himself. we just set his bed up but he's not ready to sleep in it yet. i'm hoping he'll get used to it soon though since we'll need the crib in a few months for esme.