LUO YAN had to go to school ahead of Luo Jin. It's because he was meeting someone and the time was a bit earlier compared to the usual time when he and Luo Jin arrived at school.
And yes, the one he's meeting with was Huang Wen.
After that incident yesterday, he decided to talk to the other. But since he didn't have Huang Wen's number or even his WeChat ID, he had to ask their classmates first. It's a good thing that the first person he asked managed to give him what he's looking for.
After getting Huang Wen's WeChat ID, he quickly messaged the other. Asking to meet today before their homeroom started. The other didn't reply, but he had obviously read the message as there was a 'seen' caption under it.
Since Huang Wen read it, Luo Yan just assumed that the other agreed. It's better that way than assuming that he didn't. What if the other went there and he didn't? Then, they would have missed each other. So, to be sure, it's better to just go.