Margaret,
I’ve made this one with ages 7-10, it is very simple and they loved choosing their own colours and making stars with different coloured points. Some stuck them together as suggested, others turned the points around.
I used regular orgami paper (15cm by 15cm) that I had cut into 4 squares, each square being 7.5cm on a side, so that each star point turns out about 10cm long and 5cm across. You need the equivalent of 2 sheets per star (8 points).