This is a great question that I find myself answering frequently. The reason you are the only one in your family with artistic skills is because you have chosen to practice and hone those skills. No one is born with artistic ability though some people tend to be naturally drawn to a specific art form whether it be drawing, music, sports, dance, culinary, words, acting, etc. Anyone can be taught these skills and those that are good at their particular art form are good because they practice and because they seek out new ways to improve upon those skills.
I give my drawing students a 300 Box Challenge. Over the course of the semester they are to draw 300 boxes; every time they open their sketchbook to draw they warm up by drawing 5 or so boxes practicing different perspectives and points of view. Musicians practice their scales, athletes work out in the gym; always strengthening their foundations, going back to the fundamentals and doing what they need to stay on top of their game. If one slacks off for a couple of weeks they notice that they are not doing their best work and it takes time to build up that muscle memory again. Practice. Practice. Practice.