This is a tough situation. First, I would ask you to pay attention to your feelings as you practice and play. Do your feelings of dissatisfaction fluctuate? Is your unhappiness due to any particular part of being in girls’ basketball? For example, you may still enjoy playing but no longer enjoy the stress of competition or you may still like basketball but not get along with the coach or some of the girls and that’s why you don’t like it anymore. In other words, is the dissatisfaction true dissatisfaction or primarily due to current circumstances?
There is a value to sticking with something through the inevitable emotional ups and downs of any long-term commitment, but there is also value in being able to recognize when an activity is no longer fulfilling or worthwhile and making the difficult choice to leave or change that activity. Your parents are clearly proud of you and you are probably right in thinking that they would be disappointed in your decision not to continue with basketball, but it is unlikely that they will be “devastated”.
Your parents may have several reasons for encouraging you to participate in a team sport, such as basketball. They may be thinking of the value of learning to be part of a team, the social experience, developing a sense of competence and mastery, and a desire to see you maintain a healthy level of physical fitness, along with other reasons. Parents may also have ego-based reasons for wanting you to continue. Maybe one of your parents didn’t get the chance to play basketball and wish they had or maybe your parents gain feelings of pride and personal self-esteem from having an athletic or high-achieving child.
If you decide that your dissatisfaction is due to a true shift in your desire to participate and those feelings are unlikely to change, I would suggest talking to your parents about your desire to stop playing or at least to stop playing competitively. I would discourage you from quitting impulsively in the middle of a season and informing them after the fact. Finish the season, talk to your parents and to your coach, and then withdraw if you feel that is the right thing to do. You may have to deal with some disappointment, upset or lack of understanding on their part, but ultimately you are the best person to decide what your needs are and how best to meet them.