If she's not drinking, you could try the lactose-reduced cat milk. Ours loves it, but then she also drinks a lot of water from her own personal pint glass.
The cat will be as fussy as you allow it. We had we fed bog standard cat food. When we dropped a Christmas card into the old lady down the road, it was sleeping on its own chair in her lounge.
"She only eats fresh fish - nothing else" we were told by the old lady...
I hope you have many happy years together.