This past week, I worked with two adorable second grade graduates who wanted to make American girl Doll dresses for their dolls. We started with the wrap dress. Watching them helped me better understand what makes cutting fabric difficult for them.
The first is cutting. Since small people have small hands, the obvious choice seems to be small scissors. But that is not the best choice. Small scissors make it difficult to cut a long smooth even line. They end up leaving choppy crooked lines. So try to have your child work with the larger scissors...
Which might bring you to your second problem, larger scissors tend be used around the house more often and can be dull. It is difficult cutting fabric with dull scissors and adult sized hands,and it is even harder with small hands. Dull scissors require greater strength. Dull scissors leave very messy edges.
1. Too short, will create choppy edges.
2. Bigger and sharper is better.
3. Old household scissors can be dull.
So sharper larger scissors, with supervision, may be better.
My favorite sewing scissors are Ginghers. They are $21 from Amazon, but in the long run, a very worthwhile investment.
See examples below.