Thank you, Gang!

Sorry I didn't see your reply earlier. This is really helpful.

I think part of my remaining confusion is rooted in whether when I change the value of quantitative variable in the model if I am changing my interpretation in the slope or the intercept.

For example, would it ever be appropriate to rerun the model age (or another centered quantitative variable) at different values to see the effect at "high" "average" and "low" values of that variable? Or have I conflated what we are getting with the output there? I am trying to understand under what contexts you would want to see that variable at different values and what that's telling you (and what it's not telling you).
For example is this ever done (assuming age centered at min age) to look at differences of effects at different values of age? Or if this changing interpretation of slope, I'm trying to understand how to appropriately change my interpretation across these three options.

-gltLabel 1 'ageearly.rew-pun' -gltCode  9 'Ant : 1*rew -1*pun age : 0' \
-gltLabel 2 'agemid.rew-pun' -gltCode  9 'Ant : 1*rew -1*pun age : 1' \
-gltLabel 3 'agemid.rew-pun' -gltCode  9 'Ant : 1*rew -1*pun age : 2' \

Two additional smaller questions:
1. If I center my variables ahead of time, do I still need to use qvars and center again (or if not "needed" is it recommended)?
2. I noticed when I ran additional F tests, the output gives me ChiSquare results and the results seem incredibly robust and don't seem to be taking age into my model. In other words, they do not seem accurate. For comparison, My T tests give me the coefficient and a Z score. Would I treat the ChiSquare results as F tests where they function as both the overlay and threshold? Or have I done something incorrect here?

        -glfLabel 1 'val_age' -glfCode 1 ' Task : 1*rew & 1*pun age_c :' \
        -glfLabel 2 'val_age2' -glfCode 2 'Task : 1*rew & 1*pun age2_c :' \
        -glfLabel 3 'rew_age' -glfCode 1 ' Task : 1*rew age_c :' \
        -glfLabel 4 'pun_age2' -glfCode 2 'Task : 1*pun age2_c :' \

Thanks again!