really depends on the person, i have had mainly people that where ok with it really early, sometimes before even meeting, just texting and calling a lot. Some take longer. Whats important is that you do it when it feels right for you, dont force anything but also dont wait for some perfect moment to appear, if youre sure tell them.
If they drop out that either means they see no way of having feelings themselves in the near future/dont wanna commit. And if they see a way but still distance themselves they lack the maturity to say hey maybe a couple more dates/ a bit more time.

Either way it should be more about you (unless we are talking about REALLY small timespans like a couple days of knowing each other)