Why Would I Want To Lose Weight (Muscle Mass)?

Here comes a bunch of noob questions. So please bear with me ☺. Currently I'm 5'7", and 153 pounds. When I went through my profile to set-up a goal... I choose the goal of wanting the "fitness model" body. However, it mentioned I'd have to loose close to 25 pounds. Being muscle weighs more than fat, my added weight has been muscle. I do have some fat that I'm working on in my belly area, but the rest of me is making great progress. Can someone explain this too me?

I'm new to all this, but not new to working out. I'm kinda figuring things out on my own unfortunately😞

by sledgurl07 via Bodybuilding.com Forums - Female Bodybuilding