You're way low on OG, I know that much....I assumed brown sugar was 1 qt/lb, (not sure on this, but if I picture a package of brown sugar, I figure it's about 1 qt, maybe?), and your 3tbsp / 2 cups water is 1.018 OG.
I guess they'll still eat the sugar, right? Brown sugar is fully (almost) fermentable, so they will reproduce. They won't be used to the maltose type sugars that will be in the wort, but they are yeast, they are meant to eat any sugars around, (within reason).
So, in short, I have no idea, but vote for "you'll be fine"....at least I figured out your OG for the experts to chime in on
