It does matter. Most ballerinas go en pointe from ages 10-12. Most of the time their dance instructor lets them know when the appropriate time to go en pointe is.

When young dancers go en pointe their bones may still be developing and the crammed shoe may cause long term damage to the bones.

A way to prevent damage is to make sure you find pointe shoes that fit to your feet comfortably but with sufficient support. Also make sure you are 100% ready to start this complicated art form, it takes a lot of practice and strength. Do not rely on your feet to take the weight of your body.

Anyone who doesn't take enough precautions to prevent injuries.

:-)