Virilization can start at any dose. It varies from woman to woman. The problem is you don't know what your limit is until you reach it...and then it can be too late.
She really shouldn't try a steroid because it made her trainer look good. There are probably a lot of reasons her trainer looks good. I know you are here asking questions for her, but her best bet is to get on this site herself (I'm sure Needto would hook her up) and let her ask questions to some of the experiences ladies on this site.
A good starting point would be to list her diet, bf%, goals, workout routine and how long she has been working out.
Good Luck,
Rebecca D