could a cat get more shy with age?

A cat's personality can change at any point in its life, whether it's a kitten or an older adult. That being said, there is ALWAYS a reason. Cats are very easily affected by their environments, so even something as simple as rearranging the furniture can cause a seemingly unrelated change in a cat's attitude.

When a cat is shy, they're obviously not confident, and confidence is very important to a cat's happiness. I don't know your cat's particular situation, but I can try to give some general advice.

If your cat is hiding away at all, like under a couch or bed, or on top of the fridge, (basically anywhere that's difficult to reach) block those spaces off! You don't want her to be able to "disappear" from the rest of the world. You can try out some cocoon beds, beds that are almost completely covered except for two holes they can get in and out of. Put them in socially significant areas, like the living room. It will allow her to feel like she's safely tucked away without letting her disappear, and it will also encourage her to come out more.

If she likes to climb, then give her more places to climb! Cat trees, shelves on the walls, etc. give her spots to claim as her own and watch the rest of the world from a place she feels safe.

Figure out where she feels confident (on the floor or in the "trees") and give her more of those spaces to be! Treats are also a helpful tool to coax her out of hiding or onto a new perch. Cats need to be confident that they own their territory to be confident with others being in their territory.

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