I don't see a problem with it IF you (or whoever you are referencing) is strict/conscientious enough to do it correctly. I do VERY few lifts, including assistance movements, with younger athletes. I'd rather have them know exactly HOW to do something and perfect it rather than jumping around, never really getting good or understanding anything.
So it's not so much a "yes/no" answer; there are a lot of variables in there and honestly, without one/one coaching for a long period of time and getting to know/understand the lifter, it's almost impossible to answer. If you do choose to do it, follow the principles of "start too light/progress slow". A 17 year old has a long time to improve and I see way too many people fall into the "add weight to the bar as quickly as possible" - somehow equating training with testing.