Physics is an excellent choice. For AQA Physics A:
AS: Not so hard. You study electric circuits, direct current, fundamental particles, motion in the straight line, moments, direction of forces, materials and light waves.
A2: Gets harder. You study circular motion, simple harmonic motion, alternating current, magnetic fields, gravitational fields, electric fields, ideal gas laws, nuclear radiation and a topic of your choice (astronomy, medical physics, physics experiments or practical physics).