You’re absolutely right about that. My parents were in their forties when they had me, and I didn’t have any of my grandparents for long. My husband’s mom was in her early twenties, and his maternal grandmother is still with us.
My last great grandparent died when I was 36.
I grew up in my little hometown of Hanover Michigan with grandparents and great grandparents less than 5 minutes walk away and ended up conservative.
My cousins all grew up in Ann Arbor, Kalamazoo, and Minneapolis and almost all of them grew up super liberal.