Student or Learner
If I say "we guessed the new teacher's age", does that imply our guess was right?
It doesn't to me.
It didn't at first, and then upon re-reading, it did.
If you weren't correct or you don't konw if you were correct, then "We guessed at" or "We tried to guess" would sound better to me.
I'm sure "guessed at" is going to raise some comments.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.