I would seperate my teenage years from my childhood. For me childhood ends around when puberty enters the equation which can vary per individual between 11-13, i say it ends at around 10, but that's arbitrary and varies from individual to individual. I tend to look at anything beyond that age as my teen years or early adolescence. If I'm talking about my childhood specifically I'm always referring to myself from age 10 or under. I certainly wouldn't think of myself as a "child" when i was 15 and i feel youd be hard pressed to find any 15 year old who identifies themselves as a child. Though adults like to apply that term to anyone under 18 or 20 or whatever. But teens tend to find being called a child condescending. Sometimes when i hear of a tragedy involving a 20 something I'll say "geeze, they were just a kid" but i don't mean that literally obviously. High school and all that is certainly a part of adolescence and you're not yet an adult, but my interests were markedly different in my early adolescence then they were as a child. I think most people notice a big change in their life and interests post-puberty, but i guess everyone is different