Underage in Tennessee

My question involves criminal law for the state of: TN
I was wondering is it illegal if underage to even be in the presence at a home? As well as a it illegal to be underage in the presence of alcohol at a house party? Because I have had friends get underages for being at house parties recently while saying there were completely sober. Now i don't know if I believe them, but I was just wondering for my own knowlege.

Thanks for any help or knowledge given.

No it is not illegal to be "in the presence of alcohol". Otherwise, how would you be allowed to eat at restaurants that serve alcohol? How would your parents be allowed to drink around you? if you are talking about possession, that's a whole different animal.