Another thing that I did... DD went into her big bed at 18 months in preparation for DS's arrival. She was a bit scared of the "bigness" of the space. So we put a bed rail on one side, the wall on the other, and her favorite teddies stood guard about half way down the bed, creating a false "foot" of the bed, if you will.

We also put her old cot mattress on the floor beside her bed, and she knew that she could get off her bed and go to sleep on the cot mattress if she chose (she hardly ever did that).

We also made it a really nice place to be. Her bed head had two little book shelves, like little hidey holes. So we put little plastic farm animals in there, which she liked.

And even though she had new sheets, blankets etc, for the first few months she still slept with her cot sheet and blanket

Your DD will get there in the end try not to stress about it, you've still got quite a bit of time before gorgeous no. 2 arrives