So all at https://www.artstation.com :)
https://www.artstation.com/acms
https://www.artstation.com/guraziu
https://www.artstation.com/faustodemartini

I believe there is no age for start 3D / 2D : only enthousiam is necessary!

Bon courage!

Take a look at this one : more diversified than robots or weapons! ;)
https://www.artstation.com/pao