Old age?

Well my cat isnt that old about 8,looked like she was losing weight,not. It must have been me just paranoid?? I did weigh her at vet and same weight 2 months ago,only thing i see a diffrence is it seems like her  back/spinal cord just seems more noticable,depending on how she sits?? Not sure if its just something normal,or something i havent noticed in the past??  Any1 else have this?

8m is too young to have those kinds of changes based on what we call old age.  Has anything changed?  Food?  Water intake?  Activity level?

I switch food alot,b/c she doesnt like eating the same thing,one thing i know i need to do is my food for 7 yo and over,not sure if that will change anything?? Water is normal,she likes spring water

Is she on wet or dry food?  A lot of the senior formulas are unnecessary, some are not even appropriate.

only dry she will not eat wet,ive tried. She acts normal and playful btw