Yes. Being a member in the FFP of your "home" airline comes recommended most of the time, especially since you'll be flying AA most of all oneworld airlines. And AAdvantage is not a bad program at all.
Plus, as US residents, you have a lot of good non-flying AA mileage earning options with their co-branded credit cards (speaking of those, BA also offers CCs in the US - click - something I'd consider when choosing FFPs).
It's just that BA is a good choice for not-really-frequent flying families, especially when redeeming those Avios on non-BA flights where their ridiculous surcharges on award tickets aren't an issue.