The avarage is that almost everyone who starts playing guitar gets frustrated because it isn't easy. The ones who end up learning how to actually play the instrument do so by not focusing on how long it takes. This is simply a toxic perspective. As Mo pointed out "it takes as long as it takes". You are asking your body to do something complex, demanding, frustrating, and difficult. Everybody has a different body and life experience. This makes any comparison to others learning experience as an apples and oranges debate.