It depends on what email rules does your T have. Have you talked with her about it? There are all kinds of Ts, some allow email only for scheduling, others require you to ask for a reply to get one and so on.

On the other hand, a more personal email requires more thinking before sending a reply and therefore more time. My T replies to emails within 1-7 days. Sometimes I wait for 5 days and get something like "let's talk about it in session". Ts are also human, sometimes they are too busy, not in a mood or smth else, and therefore we have to wait. And it sucks. But what can you do except wait...