Hi,
Just my twopence worth here.... I know nothing about the machine, but I do work with youngsters as a volunteer for our Quilters Guild and the one thing I have learnt is that a speed control on the machine is a must. Young people tend to press their food hard down on the foot pedal making it difficult to control what they are sewing. Slowing down the machine so when they get "lead foot" means that they can still control their project under the needle.
Learning to control the speed of the machine with a foot pedal comes with practice and experience.... and I have to say that I sometimes slow my machine down to make control easier and I have been sewing for many years... and I am a few months older than 10 - LOL LOL LOL.
Hope this helps and good for you getting your DGD into sewing... I am sure she will have many happy hours sewing with her Grandma.
Hugs
Caroline