“At what age can you start wearing contacts?”

You can wear them now but you need to be careful with hygiene.

If you feel you are ready to start wearing contacts, you have to except the responsibility of wearing contacts. That means being certain never to sleep in them at night, using very good hygiene when taking them in and out, not over using them over over wearing them, taking them out whenever I get irritated, and committing to the ritual of learning how to put them in. But at 16 years old, my daughter fely she was responsible enough, and if you feel that way too, there is no reason you cannot start.

As early as 8-9 years. Depends on how good and responsible you are.