who?
Anybody can, with a litle imagination and patience, experiment with a camera obscura or a pinhle camera. The process of image formation is a simple one and since it happens anyway in the eyes of those who read this lines, why not in a home built camera? Age is not a limit and all you need to start is a box, a tiny hole and some photosensitive material: photographic paper for instance. Think of it: the beer can is the world most used pinhole camera and the shoe box is in front of the "my first pinhole camera" list, almost no investment is needed.
why?
Because otherwise you'r missing out on almost 150 years of analogical heritage. Because you can customize your camera, fitting it for each subject, in such a way that you can obtain the wildest view angle at a fraction of the commercially available ones. Because you can play with time and motion at such lengths no other medium can allow it. And because it's fun ! Digital is't bad, only it has limitations. So has lensless photography. Play a little with your expectations understanding the upside and downside for both techniques.
when?
It isn't a right time to shoot pinhole. Do it whenever you feel like it. Make long exposure cameras and forget them for months or years in continuous exposure. Buy custom crafted ones which are almost as quick as the one with lenses. Take them with you, mount them in the garden, point them in to the sun and experiment as much as your imagination would like. There is no rush, no harsh judgment, no must, just fun! This is pinhole photography !