We find that the human psyche does not always respond favorably to study and repetition in the absence of immediate satisfaction from desired results. As guitarists we must retain a sizeable amount of information and master physical tasks such as chords, chord changing, scales, and phrasing. Both the mental and physical aspects require repetition, repetition, and more repetition to the point of making them second nature. Alongside this process arises the predictable human response to delayed gratification: frustration.
Frustration is a feeling of dissatisfaction arising in response to not having what we want in the present moment. It is an inevitable aspect of any long term complex endeavor, and so you can be sure that you are not the only one suffering from it, nor does its presence have any bearing on whether or not you have "talent" for music. Although it is not a pleasant feeling, like all feelings it can be an asset or a hindrance depending on how we respond to it.
First let us consider the less problematic level of frustration. In my lessons I often make analogy to the angry baker hovering outside the oven door with the light on and watching the bread rise ever so slowly. Although he has done everything he is supposed to do and the results are inevitable, while watching the bread rise in its normal course of process he laments that he does not already have some bread, questions whether he is a competent chef with culinary talent since he has no bread in hand at present, and throws the recipe book across the room while screaming at the stove for not having already delivered the bread he has labored for. Silly baker! The problem for this frustrated chef is that he is indulging unrealistic expectations about how long it takes to have the satisfaction of freshly baked bread. The solution for the baker is to refer back to the recipe and get a realistic idea of how long it takes for the bread to bake.
So how long does it take to learn to play guitar to the point that you can express yourself freely? Well, that is not so straightforward to answer as the bread analogy. It is going to vary a great deal from person to person due to a number of factors, but what you should understand is that it is going to happen over a period of months and years rather than weeks, so be realistic. If you are allowing yourself to become overwhelmed with frustration over some new song, skill, or technique that you started working on two weeks ago, that is not realistic and it does not help you in any way. So stop it!
Now let's consider the more troublesome deeper level of frustration that arises after you have in fact been doing all the right things that you know to do for a long time and it still seems that you are not getting anywhere. This is the kind of frustration that can ruin your experience of guitar and often leads to reluctance to practice, long periods away from the guitar, or giving up altogether. Therefore, we must have strategies to deal with this kind of frustration in order to prevent it from derailing our musical endeavors.