Is this a serious thread?
1. You're not that muscular. At that height and bf%, you'd need to be 85-90 kg before I'd call you muscular.
2. As others have said, losing muscle now is something you'll likely regret when you're older.
3. Losing muscle likely will make you slower unless you're going up hill. Most of the top TT/Pursuit guys weigh more than you.
If you really want to lose muscle, eat less and don't do any short, intense work with your legs.