Something that was part of the Manhwa but isn't mentioned here in the Anime. After Jinwoo left and Baek talked to the others, when Baek says that Ahn has to recruite Jinwoo no matter what.
In the Manhwa he says "Why haven't you recruited him yet?"
And then mentally his says to himself "To be so confindet against me... I should be prepared to lose an Arm in a Fight against him." and after that he says to Ahn "Hurry it up. Now.".
So yeah, based on the first 2 Epsiodes we know that Jinwoo is at least A Rank and probably very high at the top of A Rank.
But with fighting Barca and leveling up again, he could maybe be already be very close to S Rank or maybe even is low S Rank.
Since even Baek recognizes him.