I was once told that our bodies metabolize cannabis differently when it's ingested orally as opposed to smoking it. Not sure if that's true, but I can attest to being WAY more blown out from edibles than I have ever been smoking some flowers.
This is true.
First of all, when smoking roughly 20-30% of the contained cannabinoids are destroyed outright by burning, and a certain amount exhaled. But the stuff that you inhale gets right into your bloodstream within a matter of seconds. When eaten, you will absorb 100% of the cannabinoids, but a similar proportion will be instantly metabolized by the liver before getting into the bloodstream (called the "hepatic first pass effect"). On the other hand, the overall release into your bloodstream will take far longer as the cannabinoids are absorbed slowly from the digestive tract, rather than within seconds, as from smoking.
More importantly, eating does metabolize the cannabinoids differently. In particular when eaten your liver converts "ordinary" delta-9-THC to 11-OH-THC which is a far more "psychedelic" cannabinoid, explaining to a large part the more "trippy" effect associated with eating.
Qualitatively, eating the cannabis means it takes far longer to feel the effects (usually two hours after eating), but they come on in "waves" (you get high. ..come down a little. . .get even higher. . .come down. . .get even higher yet. . .etc), and can be VERY intense.
Its *VERY* easy to overdose on eaten cannabis, and in fact, its almost a "rite of passage" to the point where many if not most people who eat the stuff overdose on their first try! Typically someone will eat a brownie (or whatever) not feel anything after an hour, then eat another one. BAD mistake!
What you need to do is in making it, be METICULOUSLY careful about dosing. Throw a carefully measured amount of weed into your butter, then make sure its distributed throughout your final product so that you have to eat a moderate to large amount of it to get the proper dose. For example, having to eat a large brownie, or several cookies to get a full dose is good.
You don't want a situation where your dose is in, say, one square inch of fudge, because its really easy to cut a piece that is 1.4 inches on a side, and thereby end up with a DOUBLE dose (1.4 x 1.4 = nearly 2).
Also, since eating the stuff is much more akin to a "trip" that can last literally 8 hours, this is not something to be done lightly. You pretty much have to block off half a day to do it, and in my experience, you also may want a half a day AFTERWARDS to recover, because eating the stuff can leave you with what amounts to a pot "hangover" the next day!
If you've never eaten the stuff before, start small.