When I am asked the question, "How long does it take to learn guitar?", my out loud answer is, "Anywhere from one day to one year."
My inside-the-head answer, however, is, "That depends."
There is one factor that weighs more heavily than all the others when it comes to how fast we learn guitar: How many guitar-playing friends and professionals do you know personally? The higher the number of people you know, the faster you'll learn guitar. How does this work?
The more people you know, the better the chances that they will start to want to play music with you. That's a pressure that you want. The more guitarists you know, the more likely you'll have support when you need it. The more guitarists that you know, the more you'll want to hang around and play music with them.
Let's say you agree with this idea but don't know where to start finding guitar-playing friends. That's easy: Find a guitar teacher first.