adult single vacations

Marriage Advice:

Can I get a single pack of cigarettes through customs? (under age but traveling with adult to US)?

I’m in France on vacation with my gram and I’m going back to the US tomorrow. One of my friends over here who smokes bought me a pack of cigs and I want to bring it with me in my suitcase, so not in my carryon… wait, can I do that? Ok so 2 questions:
1) Can I bring it in my carry-on?
2) Can I bring it in my suitcase?
I’m only 15 but she’s like over 60 so would they maybe think it was hers? Our suitcases are separate but they aren’t marked so… idk. HELP PLEASE? I mean i’t's only ONE pack?

Customs In France won’t worry what you take out, it’s what you bring in to the US but in main luggage is unlikely to be an issue