Bigger doesn't necessarily mean older, but more than likely it will be. What you have to do is get to know the plant or the even the way they grow the beef or pigs. You said you were thinking it could affect tenderness and flavor. Other than the feed the animal eats the last 30 days, the stress it goes thru prior to killing is the most important thing for determining tenderness. There is chapter in books that have been written that cover this topic. Just do some searches and some research.
"Trust Your Butcher"
Often Imitated, but never Duplicated