The only reason marijuana is ever a gateway drug is because they classify it together with hard drugs. I'll tell you what happened with me and my friends. We went through D.A.R.E. As kids and were taught all the stuff about how all drugs were horrible and would ruin your life. When we got to high school we started meeting kids who smoked pot and realized that they were actually fine. They still did well in school and had no problems caused by pot smoking, and they had fun when they were high. So we tried it, and liked it. Later when we were presented with opportunities to try other things we figured " hey, pot didn't hurt us, so they were probably bullshiting about the other drugs too." so we tried those. In my case, I just experimented and never got addicted to anything. Other kids I knew did end up with addictions. Some of them have cleaned themselves up and are fine now, other's still struggle and suffer with it, and more than a few have died. I really believe that if marijuana were not included in the same category as drugs that are actually dangerous less kids would have moved on to harder things. If they classified it with alcohol, for example, the only thing it would lead to is alcohol. If they made a clear separation between that and other things in the educational system, it wouldn't lead to anything. Write your story about how the kid smoked pot and had no negative consequences so she figured the other drugs would be okay too. That's realistically how it often happens.