Hm...thats very odd, it usually doesnt take that long for my firecracker to hit.
I dont make 'em that often, as I just dont really fancy them that much, but they usually dont take that long to hit when I do. It could be the amount of bud that you're using, the potency of the bud, your baking, etc etc.
I find firecrackers to be very creep-ish. Instead of hitting and hitting hard, it takes a bit to come up completely, but signs are first apparently pretty quickly.
When I eat an edible, I usually eat a good amount of it, as like I said I eat edibles when I have nothing else planned and just plan on getting high out of my mind and probably falling asleep (except for when I use the Ganja Glycerin), so my come up is also a bit different because of that.
LMA - I forgot that you dont really smoke that much. I wouldnt suggest eating a full firecracker at once. I mean, if the weed you're getting is just some regular mids and not anything too powerful, you might be fine with one full one, but I know that if i were to give any of my friends who dont smoke much a firecracker, I wouldnt advise eating it all at once.