Most scopes I've seen have eye relief at around 3 inches. At that range the sight picture should match the scope, with no dark circle around the image.
However, there are also intermediate eye relief scopes, and long eye relief scopes, that are intended to he used at longer distances from your eye.
If you can, shoulder the rifle and get a cheek weld and aim as you would if you were shooting and get someone to see where the scope is in relation to your eye. If the sight picture does not line up, and you need to lift your head up or lean forwards, the scope needs to be moved or replaced. Depending on the setup something like a cheek riser that allows you to get a cheek weld slightly higher from the bore to allow you to properly use the scope without contorting yourself. A different length of pull might be necessary.
Or maybe just a different scope is required, or see if you can maybe slide the scope further forwards in the rings, or get extended rings.
When you are adjusting the zoom on the scope, you should not need to move your head at all. Though that could easily be a reflex action, just like how some people will lean to the sides while driving cars in video games. If that is the case, all I can recommend is lots of practice and staying aware of what your body is doing while you're shooting.