The main rule for mirrors is that the angle of incidence equals the angle of reflection . When the mirror is curved, the rule still holds. It can be confusing to figure out just which beams of light are relevant. The key to solving the problem is to realize that while light goes off in all directions from every part of your body, the only beams that you see in the mirror are the ones that hit your eyes. The angle of incidence is zero, so the angle of reflection is too.
Curved mirrors are interesting at any age.
It's good to give students mirrors to hold and play with. You can also get Mylar from those shiny party balloons. These days, you can also find highly reflective wrapping paper. Just be sure you can see yourself well enough before you buy. As students get older, they can take their knowledge in different directions.