As a follow on, I just re-read the thread and noticed it's only your 3rd batch. I brewed plenty of stinkers at that level!! Assuming good sanitation, the most important variable in fermentation is temperature. The temperature of the beer, not the air around it. During active fermentation, (1st few days when bubbling like crazy) your beer can be as much as 10 degrees higher than the air around it. Too warm can definitely lead to off flavors. Consult the yeast company for ideal temperature for strain. As the ferment slows, you have to raise the air temp so the beer doesn't cool. The best setup is an extra fridge with a temperature controller. Low tech solutions include moving it around to different locations in the house, ice water baths and blankets.
Another very important variable is aeration. Most new brewers and even some experienced ones just don't get enough oxygen into the wort before pitching the yeast. They shake the carboy for a few minutes and call it good. This results in all kinds of fermentation problems including off flavors and under attenuation (not getting down to final gravity). I read a study done by White labs that showed 5 minutes of the "shake and splash" resulted in less than half of the required dissolved oxygen yeast need to get a proper start for a good ferment. I use an oxygen tank and metal air stone to inject oxygen into the wort. The same type of stone and an aquarium pump works also, but you have to leave it on longer (at least 10 minutes vs 1 with O2). This is especially important if you are only pitching a vile or smack pack of yeast. This is "underpitching", or not pitching the recommended amount of yeast for a given gravity beer. Since oxygen is a key factor in yeast reproduction, you have a two-fold problem, not enough healthy yeast to ferment your beer properly.
I'm off on this rant to stress the fact that we make wort, it's the yeast that make the beer. A fairly boring, plain-jane recipe that has been properly fermented by happy, healthy yeast will very likely taste better than the most creative, delicious sounding recipe that was under-pitched, under-aerated and not temperature controlled.
All this said, your beer will very likely still improve if you let it age. I've been disappointed by many a first taste and it never ceases to amaze me how much a month or more cool in the bottle or keg improves a beer.
Welcome to the world's best hobby!!!!!