It would help to have more context. I'm going to guess. I could be totally wrong. It might be a joke about a party.
At a party, people start by being reserved and polite. They talk about safe subjects like the weather. As they relax, they start to "warm up." They start to discuss more personal things. Eventually, they start to gossip and tell secrets.
In this gathering, it is still early. They have not relaxed enough to be telling secrets. "Nobody's told any secrets yet."
Why "even?" Maybe the speaker expects more. "Have they put lampshades on their heads yet?" "No, things haven't gone that far. Nobody's even told any secrets yet."