Help

Let me explain - I (15M) am currently a freshman in highschool, and I play piano. I have been taking piano since 2nd grade, but here's the thing; I've lost interest and my parents still think I love to play. My piano teacher is a very sweet lady who I think of like a grandmother, as I've been seeing her for lessons for about 8 years. I want to quit, but I don't know how to tell my parents. On one hand, they recognize I haven't been practicing much recently but they think it's because I like to spend all my time on my computer, but if I still had interest in piano, I would much rather practice then be on a screen. On the other hand, they would be understanding and say it's my choice, as its my extracurricular - it's really a 50/50. I'm just worried that I will get yelled at and it will end with a long argument that didn't go as planned. Also, my teacher enrolls me in competitions I don't want to do as it is just stressful for me. Thoughts?