Can you try it without the rail (like a daybed)? DD moved to a twin bed at 2 yrs. 3 mos. and has been fine in one since. We did try a bed rail with the twin bed, and I couldn't get it to fit right so we opted not to use it. She has only tumbled out of bed three or four times in the last 16 mos. or so, which has been fine with me, but I know three or four too many for others so it's really your call. I'd hate to spend the money on the rail for a 2/1/2 year old if she may end up not needing it.