I see nothing wrong with teens training with adults. Of course, the teen needs to be mature enough to handle the adult class, seeing that most adult classes are structured differently than a kids class. The material taught, the intensity of the class, etc.
Its a benefit to them, because they will get the chance to experience larger people attacking, and it'll force them to really get their material down.
As far as working with things that may be a bit risky, ie: grappling, etc. I feel that things need to be done on a professional level. Sure, grappling can put you in some rather embarrassing situations, however, the odds of a female being attacked by another female are probably a bit on the low end, compared to being attacked by a male. So to always seperate the sexes is doing more harm than good.
Its a benefit to them, because they will get the chance to experience larger people attacking, and it'll force them to really get their material down.
As far as working with things that may be a bit risky, ie: grappling, etc. I feel that things need to be done on a professional level. Sure, grappling can put you in some rather embarrassing situations, however, the odds of a female being attacked by another female are probably a bit on the low end, compared to being attacked by a male. So to always seperate the sexes is doing more harm than good.