Hi Alice,
Before you get the permanent screws put in, put the skates on and lace up fairly loosely and stand in them on carpet or vinyl flooring (without the guards on), to see if you can balance on each foot at a time. Hold on to something or someone when you try that. Your body's natural ability to balance will soon tell you. As the last person suggested, lace up normally and try them on the ice too.
Good luck, Robert