As you’ve probably seen stated elsewhere on this site before, - and probably heard it from other sources as well - it is no secret that not all people are able to gain muscle-mass the same way and at the same rate. There are some, whose genetic structure allows them to simply pile on pound after pound of muscle, others have a hard time seeing any bit of result.
Ultimately all of this is only important from a psychological point of view. Seeing fast results can be a great driving force, a huge self-confidence booster and generally a positive thing altogether. However this doesn’t mean that being a slow developer means exactly the opposite. While it can be hard for morale to struggle along whilst others have all the fun, basically what’s important is that one develop at the maximum pace his/her anatomy and genetics allow.
If one will be able to keep that pace up, they can easily consider themselves successful bodybuilders, no matter how quickly or slowly they gain muscle mass.
The problems come - both for fast and slow developers - when for one reason or another they develop more slowly than their organism would allow them to.
For fast developers, all the positive feedback concerning the gains they make, can simply backfire on them. Overconfidence that their bodies are “genetically programmed” anyways to gain muscle fast, may lead to sloppy training, and generally a decrease in interest for the quality of a single training session.
On the other hand, slow developers are prone to fall into the habit of comparing themselves to “overnight success” guys thus losing out big as far as self confidence and motivation goes.
Don’t ever compare yourself to anybody based on how long you and he/she had been training. It’s simply not a basis for comparison. Last time I checked judges at contests didn’t look at how long this or that or the other individual had been around, and how famous this or that or the other contestant was.
Focus on one thing: Bring the max out of yourself: develop at the max rate your body allows, be that fast or slow