Dont be too quick to take it off her, give her loads of fuss and just wait till she's ready to give it up (that is if she aint f****d off with it) if she does piss off, then just quietly put her lead back on and call it a night, keep a couple of rabbits for training with, they will tend to f**k about a bit the first few times, as it feels different in their mouth, unless you've already used rabbits to teach retrieving!!!
most importantly, remember she's young and you've got her for years to come so dont rush it too much now!!!