I was just about to type that out before I saw your edit. 
It can be a tough thing in manga to differentiate who is speaking sometimes, but you’ll start to get a feel for the speech patterns of each character as you read, as authors usually give individual characters different styles of speaking (such as different levels of politeness, or certain verbal tics, or something along those lines).
It’s also a little tough since this one introduced 3 characters immediately, which means you only have a 33% chance of guessing correctly.
At least in my first manga (Takagi-san), it was a 50/50 shot, and they had very clearly different speech patterns. That still didn’t prevent me from messing up all the time and having to re-read to clarify I knew what was happening.
But! If you stick it out, you’ll see progress, and there’s always wonderful people here in the club who are willing to answer any and all questions. Like I mentioned in the home thread, no such thing as silly questions in this kind of environment. We’re all here to learn and have fun. 










