I would keep it short in the beginning, and if she e-mails you back, then feel free to talk more. The first e-mail I would send would probably read something like this:
Hey, Counselor. Do you remember me from camp? I just wanted to ask you how you were doing and everything. -Me
Okay, that's a pathetic example, but you probably get my point. I wouldn't send her a long e-mail the first time around, especially if you did not spend a lot of time around her at camp.
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