My 4 year old is still in a toddler bed with an extremely small bed rail at the head of her bed. When we first transitioned her to the toddler bed (2 yrs)she fell out every night, several times. I felt like I was breastfeeding all over again; not getting enough sleep. I told myself that I would give it 1 1/2 weeks and if that didn't work, I was putting her mattress on the floor. That didn't have to be done b/c she learned to keep herself up there. When she stays the night at both grandparents house she sleeps in a full size bed by herself and never falls out. I think if you have a wall that you can push the bed up to for one side, that would help alot. How is she doing with her mattress on the floor? Do you have to pick her up off the floor? If so, I'd probably keep it there awhile longer. If not, I'd go for it. :) Good luck!