K.M.
Hi M.:
I hope I don't offend you, but, I think toddler beds are a huge waste of money.
You will be needing the crib mattress for the new baby, right? And you will also need a new bed (twin size?) for your little girl, right?
Why not just go with the twin set-up right away and save yourself that extra step and expense? For both of my boys, I started with first putting the twin size mattress (not box spring) right onto the floor. Of course, you must doll it up with pretty sheets and comforter to make it more enticing! Have her on the mattress for a couple of months, then add the box spring. You could even add the safety rail at this point if it seems too high. After your daughter feels comfortable after a couple months of that, add the bed frame. (You can even spread the cost out for everything; mattresses first, bed second)
I tell you, it works out really nicely for us!
Have fun and Happy shopping!
Congratulations on your new baby-to-be!