Would suggest you maintain your weight and do weight lifting with your legs to increase your muscle. If you lose weight, you will lose muscle, which will negatively affect your basketball performance.
Also, since you haven’t hit your max height, if you lose weight now, you may not grow as tall as your destined to based on your parent’s height. Girls reach 90% of their adult height by age 15 and if you lose some weight, you may stunt your growth which would be a real negative for a girl basketball player.
Talk to your gym teacher about weight lifting exercises you can do with your legs to build muscle for running and jumping. Think strength, not weight loss. Check out your school’s weight room. There may be mostly guys there, but a gutsy girl can easily work out!