Normally they do not reject if you have a TA (Teaching Assistantship) or an RA ( Research Assistanship). These credentials you will achieve in your masters degree. It becomes harder if you are an undergrad. So my only suggestion for you is let her apply after you joined masters and after you get a TA/RA or if she has good credentials and shows good intent of studying in United states to the counselor, then i dont think she would be stopped from getting her visa to US. i hope this helps!!