In addition to talking to math and physics professors at the University that admitted you, you really need to read the entire set of rules. Twenty-five pages is not long by NSF standards. In particular, you are considering a deferral for a reason other than a medical or military reason. You might qualify for reserve status, if you can fund the first year another way.

These awards are somewhat prestigious. For example, universities put out press releases sometimes when a current student gets awarded one. It is something worth listing on your CV for the first few years after graduation.

There may be a mathematically oriented program in the physics department. Something that is not a waste of time if you switch to math after one year. Something you might find interesting if you stay in physics.

Condensed matter physics today is dripping with modern math. Operator theory, C*-algebras and homotopy theory with a side-order of machine learning.

In addition to talking to math and physics professors at the University that admitted you, you really need to read the entire set of rules. Twenty-five pages is not long by NSF standards. In particular, you are considering a deferral for a reason other than a medical or military reason. You might qualify for reserve status, if you can fund the first year another way.

These awards are somewhat prestigious. For example, universities put out press releases sometimes when a current student gets awarded one. It is something worth listing on your CV for the first few years after graduation.

There may be a mathematically oriented program in the physics department. Something that is not a waste of time if you switch to math after one year. Something you might find interesting if you stay in physics.

Theoretical condensed matter physics today is dripping with modern math. Operator theory, C*-algebras and homotopy theory with a side-order of machine learning.