I've been smoking since I was 12 years old... That may sound crazy but I know people who started even younger. Growing up in Southern California, everyone smoked, and I'm only exaggerating a little bit when I say that. 80% of my family used weed heavily, 90% of my classmates did, and even a couple of my teachers in school were open about their usage. It was just a normal thing, and there was almost no question that I would too, but was this a bad thing? I think it was for me, but I know a lot of people who weren't affected so adversely.
People like to delude themselves about marijuana. A lot of them consider it 100% harmless, even beneficial. I just don't agree. I love weed, it makes nearly everything more enjoyable, but it also makes a lot of things more difficult for certain types of people. Me and plenty of friends who began smoking at an early age have noticed that we have very short attention spans compared to our peers who refrained from using cannabis so heavily when they were younger. For example I find it almost impossible to sit and enjoy a movie if I'm not stoned, and I know plenty of people who could concur. This is just one example of the negative mental effects which I've seen attributed to adolescent marijuana usage elsewhere.
Being someone who's used a large amount of drugs in my life, especially considering how young I am. The only one which has ever been detrimental to my life is weed. It's exceptionally easy for a young person to become enthralled with what is generally considered a "harmless" substance by the masses and rationalize unhealthy behaviors. In high school I would frequently neglect personal responsibilities and opportunities to grow, because I would rather sit and smoke with my friends. This caused me to have to "grow up" in a very short period of time after graduating. If you have a lazy personality then marijuana will absolutely exacerbate that, there's simply no question to it. If you have anxious tendencies you can expect the same result, and if you overuse it then this will likely bleed over into your sober life.
I won't sit here and tell anyone younger than me to stay away from drugs, because that'd be both hypocritical and impractical. What I will say however is to proceed with caution, cannabis is not a completely benign substance for everyone. I'm but one example of someone who it has impacted negatively. With that being said though, it can be an amazing thing if used properly, and I don't foresee myself ceasing the usage of it anytime in the near future. I've seen it time and time again. Someone abuses the drug during their adolescence, only to develop a very unhealthy relationship with it once they grow older. While someone who begins using it at a reasonable age has no issues. I can acknowledge that I use it as a crutch, a way to cope with boredom and emotional turmoil. I often find myself wondering how different my life would be if I found another outlet than weed (and eventually other drugs) when I was younger. How different would my life be? My personality? How much further along would I be in areas of my life that I believe myself to be lacking? Drugs change you, whether you like it or not. That's what I'll leave any highschoolers/Junior Highschoolers questioning whether or not they should try cannabis for their first time with. Whether these changes are positive or negative, you won't come out the other side the same person.