How long has she been training? What's her program look like? And her diet? What are her goals, and why does she think she needs steroids to accomplish them?
There are an awful lot of misconceptions about women and steroids, namely that they're fat burners. Arguably with the exception of Anavar, they're not. They'll help her hold onto a bit of muscle as she diets down, but 1) after she goes off the steroids, she'll likely lose any physique enhancements she gained, and 2) preservation of lean mass can just as easily be done with a good diet and excercise program. At 19, her metabolism should be whizzing along, and she shouldn't need hormonal enhancement. Hell, I wish I were 19 again and had access to a board like this - my body would have been much better for it.
Lastly, I don't know that it's ever totally safe for anyone to juice, female or male. Unless you get your stuff from a respectable pharmacy, you're kind of playing Russian roulette with your body - your AAS may or may not be the AAS you think it is, it might be contaminated, or it might not be AAS at all. Caveat juicer.