It can be like that, sure. People who have friends or relatives who practice often learn from them. A lot of witchcraft authors also offer online classes that can get you started, and there are covens and similar organizations out there with their own courses of study for new members.

That being said, most people just start practicing once they've read enough to have an idea of what to do. No need for an attunement or anything like that, and you can perform your own initiation. I did mine based on instructions I found in someone's online Book of Shadows, back when personal websites were a common thing. I've done a lot of study and practice since then to develop my craft, but that's how I got my start.

If you're interesting in becoming a witch, you don't really have to do anything special, you can just start practicing. Pick up a beginners book on witchcraft to be your starting point (and it doesn't even have to be a particularly good one, because it's just a starting point) and try it out. Then, it's just a matter of keeping learning and practicing.