Them finding out that you are a Titan Shifter
Eren
Eren is curious, for he thought that her was the only shifter for a time, but now he is starting to see that there are more just like him. You, however, liked that he knew about you know, that way the two of you could help each other.
Armin
Armin was fascinated, he was interested in knowing how you became this way, and all that you could tell him about being a shifter, seeing that you were more experienced than Eren.
Jean
Jean, at first, was freaked out. He didn't know whether he could trust you or not. However, he began to notice, that you were still you, just with a huge role to play in this war.
Levi
Levi actually almost killed you, until he realized that it was you. Him and the other higher ups questioned you, making sure you were on their side, however, when people wanted you executed, he said that he would take full responsibility for you.
Marco
Marco was okay. I'm he was spooked to begin with, because it wasn't something he thought to be possible. However, making sure you were good, he made sure that he helped you with whatever you needed, just like before he knew your secret.
Connie
Connie threw a fit, freaking out over it, then he was upset that you never told him until now. He eventually found, you being a Titan as a good thing and a pretty cool thing.
Bertholdt
Bertholdt was curious as to what side you were on. He was interested in knowing if you were friend or foe, however he was nervous as to how many shifters he didn't know of were around.
Reiner
Reiner thought that it was great. He thought that is you were a shifter, you would help him and Bertholdt with there plan. He also thought that know he could talk to you about your Titan, learn more about it's abilities.