D.M.
I was given a toddler bed around APril or May. Over the summer, I put the bed together and put it in my daughter's room. At the time she was about 18months old or so. She played on it for a couple of days and then we started taking naps in it but sleeping in the crib. Then we started sleeping in the bed while the crib was still set up. Within about 2-3 weeks, a month at most, I moved the crib out altogether and she's done great ever since. We have a two-story house, so I did start using a baby gate when she began sleeping in the toddler bed exclusively. I would go ahead and have her get used to the new bed being in there first, and then just take it slow for a month or so and eventually move the crib out once she seems comfortable sleeping in the toddler bed, then you can have the crib for the new bundle of joy and she won't feel like she lost her crib to the new baby. Hope this helps!