Hi and welcome to YT....we'd love to see pics of your new furbaby. And I'm not really one to help you with your questions but like the previous post, there's usually not talk about long-legged vs short-legged unless it's just used to describe one in detail...to me, at 12 weeks, they all appear to be "short-legged"

you really can never tell but there is a standard in inches measuring from ground to back or something like that but again I don't remember what that is. You just have to see how she grows and enjoy the transformation. I'm sure she'll be beautiful however she ends up!