My Children have always wanted to sew at a young age, because that is what I am doing. We have made tons of bean bags over the years. I let them hand sew the last little bit shut.
The only problem with teaching them to sew is that when they get a little older and they can sew on their own they will take over your machines. I have had to literally kick my older girls off the sewing machines so that I could get some sewing done myself.