How old is she? If she's 40ish, first sign of aging or diminish fine line stuff probably works. If she's 50ish, actual anti-aging or things that helps with hormonal aging/wrinkle would be good. My mom had great success with L'occitane Immortelle, Murad Age-Resurgence, and Shiseido Wrinkle Resist. I think there's kit out for all 3 lines, and suggest read the description and filter by age to figure out which ones are for you. Depending on how much she like skincare, an enzyme mask is gentle and helps with dry/dull skin, I think Ren have one for mature skin.
I love the Miracle Worker line from Philosophy for a great place to start for anti-aging products in great value sets!
That one is their $40 kit and it's great way for starting into a line without committing to a hefty price tag or products that might be too much and not work out. The line is great because everyone knows retinol is a power componenant in the anti-aging game, but retinol itself can be quite potent, so Philosophy relies on a retinoid, which allows for a more gentle and time released delivery and absorbtion into skin but still works effectively to combat lines, wrinkles, loss of elasticity, and helps with age spots and sun spots by increasing healthy cell regeneration and allowing for a chemical based exfoliation rather than one with harsh scrubbing agents that can tear or irritate sensitive or aging skin.
The pads can be cut in half to give even more use out of the kit and I love how the serum and moisturizer feel! I've used the serum on my laugh lines and have seen a difference in having them disappear and the moisturizer is very light, but does a great job at hydrating. There are other products in the line your mom can be introduced to later if she decides she likes the products!