We need help developing an online course for teens to learn Blender.
I think that using blender to introduce teens into learning 3D is not such a great choice because I believe using blender would scare kids away from 3d.
Yes blender is free but that doesn’t mean its easy to use. Like Maya, Blender has a confusing menu system and it has a steep learning curb that would more than likely misguide kids and discourage them. I would recommend teaching them on a program like modo (luxology.com) 
since the program makes it so easy to learn 3d plus it is used by many production houses to produce assets while still using other programs like maya or blender for animation or effects. modo has a really nice educational program I would recomend you would check it out. ( And not I am not getting kick backs)