I started taking lessons on accordion at age 12 years 8 months...I excelled quickly, and within 3 years was as good as most accordion players..I continued lessons for another 3 years..total 6 years...Including my theory studies and jazz arranging..
I graduated high school at the age of 17 and then went to college..and studied music another couple years..

My point ..if you are not an accomplished player within 3 years of study..you did not apply yourself and/or you need better teachers...