However, my membership still hasn’t been activated
It's Copper membership, literally, not Bronze membership.
Details about Copper membership is in its announcement thread. About activation, you won't automatically have it. First your purchase transaction needs to be confirmed, it has yet confirmed now. You need at least 1 confirmation.
Second, you have to activate it, by choosing this simple option.
https://bitcointalk.org/index.php?topic=2385104.msg24384792#msg24384792See the image in that post to understand.