oh, the irony! I love that your grandma—who’s presumably in her sixties at least—is like “*I* don’t need anti-aging products. here, my darling young granddaughter, you take them.” so the short answer to your question is yes, it’s safe to use the products. they can’t hurt (unless they’re super-major-peely-and-harsh, or—if you have oilier skin—too heavy. most older skin is dryer). mostly, I imagine, they’ll nourish your skin and make it more supple. in your early twenties, I wouldn’t rush to buy super fancypants skincare when you run out though. I’d focus on lifestyle factors like a healthy diet (I cannot stress how important that is!), enough sleep (ditto! who wants to be described as “haggard?” not I!), and never-ever-ever smoking or sunning