"Mi casa es más vieja que la de mis hijos."
Translation:My house is older than that of my children.
Yes, Just because the literal translation is "than one of my children" might confuse some, but we replace objects all the time in English. My issue is that I tried to say "My house is MORE OLD than one of my childrens" which was wrong. The difference between "older" and "more old" here is I guess the same as current American and Olde English. but if they suggest the more literal translation as correct, maybe mine should be as well