I had an interesting thought (to me, anyway). In the scriptures, we read of babies drinking milk and, when they get old enough, they eat meat. And we talk on and on about how we've got to be careful not to feed people meat (hard to digest and all that).
But, I think we forget that the word translated as "meat" in the KJV of the Bible simply means "food". "He sat at meat," means, "He ate a meal." If there is no more information, we don't know what he ate. It could have been barley bread and cheese.
So, the conflict is between a baby who is still suckling at the breasts and a two-year-old who can chew and eat most foods or a seven-year-old who can chew and eat all foods, not between a baby and a thirty-year-old or eighty-five-year-old.
You really don't have to be very old to be able to eat solid foods. All you need are enough teeth to chew the food without choking . . . and enough sense to take the time to chew thoroughly.
Read what Joseph Smith said are the first principles of the gospel (when speaking to his people).