Lift weights. Avoid fasting.
Burning fat and building muscle at the same time is very very hard to do for 99.99%.
Lift heavy, eat protein. Doing keto is fine, but I would avoid fasting at your age.
Honestly you don’t have much to lose to begin with, you’re roughly in the middle of a normal BMI.
The best thing you can do is lift and do your cardio, with that will come some fat loss. Having a healthy diet will make sure that all things fall in line
listen carefully.
unless you have a disorder that prevents muscle from being built easily, and trust me if you had such a condition it would be challenging to put it mildly for one to consider what you’re discussing doing, your best bet is to eat a reasonable food plan.
lean, complete proteins. reasonable fruit and veg. cut back on wheat.
and do moderate weight bearing exercises.
you’re a teen, presumption is male based on height. if this assumption is accurate, given the raw materials necessary your body will build muscle easier now than at pretty much any other point of your life… if you allow it to.