I have always use the hyphen when introducing dialogue.
-I love skating, but I'm not very good at it.
But I have recently been educated about the existence and use of en/em dashes. Now, I think I got a grip on the basics, but I actually didn't find anything on using them as dialogue introductions. So, what is correct, a hyphen, an en dash or an em dash? Here's all of them lined up, in case you haven't seen them all.
Also, a little side question. Is it normal, and acceptable to use hyphens and dashes as dialogue starters? I'm not looking solely for your individual opinions, as that is off-topic, but rather numbers on what the majority prefers.