Anyone training their babies to sleep in a toddler bed/twin bed yet?

We’ve been having a moisture problem in our apartment building, all the windows are wet & I was doing my weekly bed set change for my 3 year olds bed and my 1 year olds pack n play and there was mold beginning on her mattress pad. Should we buy her a pack n play or a big kid bed? She’ll be 14 months on feb 29