What is the most favored grammer for thoughts?

I like to use italics for thoughts in a memoir. I will be consistent and I am aware the publisher may change this.

Which one is most correct? (Italics were not available in the ask Jerry feature. 'Are you kidding' is in italics.)
A. I thought are you kidding?
B. I thought, Are you kidding?
C. I thought, are you kidding?

Or maybe I do not need the dialogue tag?
The manuscript is past tense, the thoughts are in present tense.

Separate question:
I have location/date tags, in italics and justified left. I want to add my age to make the math simple for the reader. Is this correct?

Anchorage, Alaska, 1997 (age 30)

Thanks, enjoy your vacation!

Jerry's Answer

B. would be correct, Heather.

Adding your age would be OK the first time, but give the reader credit for doing the math after that. :)

And thanks for your kind comments. All the best with your project.

Oh, I forgot to mention, you misspelled grammar. An easy fix. :)