I wanna get back into shape

This is my first post ever. I had weighed myself last night and I'm the heaviest I have ever been in my life. Some is muscle yes but I know most of it is fat from sitting around all the time. When I was in high school I was in marching band so I was moving and working my body all the time so I was in great shape. Granted I had no boobs whatsoever then but honestly I just wanna feel good again. Can anyone help me??? I want to work out but I have no clue what to do since I've never been to a gym or anything like that. I'm not trying to get "skinny" I want my curves but I want them to be mostly muscle. Here's an old pic of me excuse the zit on my face it was highschool. Not saying I wanna be that, but I really want to be able to love my body again and not feel like a slob day in and day out.