No, you're not stupid!
Learning to read (decode) patterns is just as big a skill as learning to knit. All those abbreviations, *'s, brackets, repeats etc can look like a new alphabet, never mind a new language.
I'm glad you worked out the answer. As you found out, sometimes going and doing something else (making a cup of coffee, walking the dog, posting on KnittingHelp) can unlock the 'brain freeze', so when one goes back to the pattern it makes sense.
An English Knitter (nationality and method).
Feel free to call me either Clutter or Julie (my real name).
FO: Downton Hat
A sweater of a thousand yards begins with a single stitch. Lao-tzu's Granny