hun, i've heard lots of friends say that making a big move AND changing beds can be very traumatic for kidlets. even if that move is just from one room to another, if you take them from their bed to another environment, it can be very scary for them. personally, i would have the bed in her new room at the new house, but still have her cot there for back up in case it's needed - just so that she still has it there. she may transition fine, but you don't want to pull all her security at once - maybe have the cot there, try her in the big girl bed, but don't fight putting her in the cot for a while if she needs it kwim?