About gaining quick it’s all individual it seems, some gain fast and some, like me and many others must work on it over time as it has been said many times it’s a marathon, not a sprint, be careful and don’t overdo it and please read through this as well Physiologic Indicators (PIs) to help growth!, you only have one penis my friend. ( unless you are like the Chilean guy with two ;) )
Anyway a lot of useful and must read info inside the newbie routine link and I recommend you reading them so you do things right, good luck gaining, it is really worth it when you feel the difference, measure the difference and the best.. when someone else notices it. ;)
Read this thread. This thread by Bennett8 is my main motivator to continue. The two of you started with the same measurements.