If your child is having a lot of difficulty controlling mouse movement and getting the mouse to stop on a desired location, you may want to adjust the mouse settings on your computer until your child becomes more proficient at mouse movement.
Directions on how to adjust this for Windows computers can be found in this article:
How do I lower my mouse speed settings in Windows? (KB000009)
Directions on how to adjust this for Mac OS X computers can be found in this article:
How do I lower my mouse speed setting in Mac OS X? (KB000008)