"If you wait till you are ready, you'll never do it" is one of the best life lessons I have learnt. Not only when it comes to suicide, but when it comes to other things as well.
Like in hobbies, for example running. I used to think "I want to start running, but I'll do it tomorrow, since it is too hot/cold today.", then the next day came and I said "I want to run, but there's this new Netflix show I want to watch, I will run tomorrow." And the weekend came and I thought "I want to run, but I'm feeling tired. I'll run tomorrow" and soon a whole year had come and gone and I hadn't run a single time. Then I just started running even if it was cold and rainy and I was tired, and soon it became a habit and it was nice to run even if the weather was bad or I was tired etc.
Of course when it comes to ctbing, you shouldn't do it lightly. And I believe that everyone should be able to ctb in the place they want, with the method they want, at the time they want.
It's true that it's very hard to know when to ctb. I'm the type of person who feels it's much easier to ctb when I'm doing well, because I feel that if life is good, then afterdeath is good too. But when life is complete shit, I fear that afterlife will be shitty too, and I'm scared of dying. My life is absolutely shitty right now and everyone would say it's a great time to ctb, but all I can think is "What is afterlife is shitty too? Besides, I want to experience A, B and C one more time!". Two years ago when my life was a lot better and I was happy I used to think "Now I have gained everything that I can realistically gain in life, I'm happy, and I have just experienced A, B and C. Now would be a good time to ctb, I feel that afterlife will be nice too.".
I wish there was a way to know when to ctb, but I have no idea.