I don't feel guilty yet, but probably should.
What did you do that you should feel guilty about?
I did something terrible.
If you did something terrible then you should probably feel guilty about it. If you don't feel remorse for bad things you've done then you might have a mental condition like psychopathy. I think you should talk to a mental health professional about your lack of guilt.
Nah, I'm good. I don't feel guilty and it's okay if I don't feel guilty. I'm not hurting anyone by not feeling guilty.
Okay so you know you should feel guilty but you are okay with it if you're not, that doesn't make sense. Try to rethink what you just said. Therapy does help, and will make your life easier if you just try it.