To learn guitar is a process, practice makes perfect.The key point to master and improve your knowledge about the instrument is practice and discuss with another guitarist. Other textbooks or even music instructors are just supplement for your skill.
To gain the best result, try to work on your skill at least three times a week for about one hour in each session. Remember, practice makes perfect.
If you are a basketball player or a goalkeeper, there is a possibility that your fingers would not have the flexibility. Thus, it may hamper your progress – especially in picking guitar.