My parents are Boomers and in their 70s. You would need each generation to have kids in their 30s and 40s to be a boomer with a gen alpha grandkid. My sister is Gen X in her 50s and has two grandkids already.

Don't forget Gen Z is between Millenials and Alpha.

Also this shows that the most common age of parents having their first child to be 20-24 up until very recently so that fecund land is your land too.