Marketo is ordering each variable based on the type of module you're defining. So because the third module is a "String" it is moved to the top.
You can test this by setting one of the others to a string and you will see what I mean.
So if you had them all as boolean it would show in the correct order, but I assume that you don't want them all as boolean.
There is an open idea here that you can vote on for Marketo to implement: https://nation.marketo.com/t5/Ideas/Guided-Landing-Page-or-email-2-0-variables-should-display-in-the/idi-p/267065
... View more