Chapter 3 - In Yarmouth, How Old Is David & Ham?

I am guessing a little on the relative ages of Davey and Ham.

We remember that it was the boy Ham who was the messenger the night David was born,  he was sent out late into the night to bring the doctor and midwife,  quite a big responsibility  So would Ham be around 10 or 12 years old at that time?

So what age was David when he went to Yarmouth -  would he be 6, 7 or 8yrs old?

Also we could guess then that the 6 foot tall,  strong Ham could easily be in the range of 18 to 20 years old?.     It would be perfectly reasonable for the description and age to fit together.