Seven-month-old mazie is crawling toward the end of the bed. how likely is it that she will continue on and fall off?

I believe the answer is: Unlikely, because depth perception develops by about 6 months of age in infants

By the time infants are crawling, they are able to perceive the environment around them and would tend to understand that the end of the bed is dangerous for them (since they could no longer see the environment beyond the end of the bed)