Considering the security at airorpts these days, it would highly unlikely though not impossible for you to sneak it in. You could be charged and arrested for possession of alcohol or they might just toss it.The bottle would show up on scanners and a largish liquid filled bottle is likely to attract scrutiny.
It is illegal for you to pssseos Alcohol in the US until you're 21 regardless of whether you bought it legally in another country or not. If it is in your carry on you'll likely get caught and be turned over to local authorities. If it is in your checked baggage you should be OK unless it breaks in your bag or you are picked for a random search.