What does it mean when you tell someone you love them?

When you tell someone you love them, it means that you'll always be there for them and have a serious realtionship with them. I think love is a little extreme for someone under the age of 18 because it means that you want to have "it" with them.-(Not always) Love is another Word that people mistake for like because when you love someone that means you'll stay with them forever. Teenagers say I love you but the guy/girl will break up with him/her one day. It all happens to teens.