Is he ready to defend himself? Yeah, he's already come to terms with the fact that he'll fight to stay alive, is willing to incapacitate people and even kill if necessary. Of course, he'll always help people first and foremost, but that includes surviving for his allies' survival.

So, he meets Bucky's look seriously, "Yeah. I'm ready," though now he cracks a small smile, "I've already survived my first scuffle."

Part of him wonders is he should mention for them not to take the first strike, to let people have the chance to leave or make peace, maybe to find some new allies, but he decides to have faith in the man he's seen Bucky be so far.