I’m 35 and I haven’t even had children, yet. If I do, I’d be highly surprised if I live long enough to see any grandkids. My grandfather was 77 by the time his first and only grandson came along... me (that was his mama that would’ve been 114). Even having children young is not necessarily a guarantee. My father became a father with my older half-sis at 21. He’s 70 now and his two grandkids are in their early/mid teens. He may have a fairly decent shot at seeing g-grandchildren if he makes it another 15 years or so.
Hubby’s Grandma got to play with her GGrandkids but she was in her 90’s. My Grandma helped me with my firstborn but died when he was 2. So the odds are against her.