Is it appropriate for me to use a white cane with low vision and physical impairment?

Absolutely! A folding support cane, painted white with a red tip, is available and entirely appropriate for your situation. There are no regulations regarding who can or cannot purchase or use a white cane in public. For persons with macular degeneration, the white cane may be the only outward sign that the individual is living with a profound visual disability.
Yes. A cane can assist with navigation and is also a signal to others that you have a problem which they should respect. It may also provide some stability if you have other physical impairments in the mix. By all means acquire this and learn to use it properly.