Alright fit or exercise savvy people of /r/teenagers: For a teenager, is muscle building or weight loss better?

Hello! I've been trying to get in shape recently, but I've had a dilemma: should I focus on weight loss or muscle gain? With a combination of logic and seventh grade biology, I've figured that you can't do both at the same time, because one requires a calorie surplus and one requires a calorie deficit, I'm just not sure which one is more important for me to focus on. As far as my body goes, I have almost no muscle (I have the skinniest arms and legs ever), but a kind of fat stomach. Part of me wants to do weight loss because that will give me a better stomach and a thinner face which I want, but another part of me wants to do muscle building because I'm growing so I still need food and muscle burns more calories than fat at a resting rate. Also, what should I do to accomplish either of these goals? I've been to r/fitness and r/loseit, and I could probably find something, but it would be nice to find something teen specific. I'm planning on trying a sport at school this year, so that'll probably help.