I eat a lot of edibles these days (all candies though, haven't actually had any baked goods) and i have an, uh, interesting tendency to eat 2 or 3 in a day, supplemented with copious smoking.
As such I feel compelled to reassure you; my tolerance is obviously significantly higher than yours but this shit is potent - it is proper medicine. A strong edible will likely have you hella stoned all day (I took two when I woke up one day and was stoned until bed time), but I mean worst case scenario you can just go to sleep, because you will be exhausted after a while, definitely once you start coming down. Moral of the story being "don't worry, have fun" - it's not like you're taking LSD or meth where shit has the potential to go really sour for a few hours, and leave you lost in the twisted depths of your own mind for what feels like an eternity.
as an aside, the high might sneak up on you, I find an hour-ish after the fact I realize I am wicked fuckin' stoned, it's more sudden than even smoking, which is more or less instant, more subtle too (though I suppose that is how it goes with so passive a route of administration)