you could still get something from her, you dont have to have sex to get stds. for example, you could get it from using dirty needles [drug use, dr offices, tattoos, piercings etc] she could also have oral herpes or some other std that can be on or around the mouth. sometimes std infected people show no symptoms ever. and most of the time people do not show symptoms till many months later. really all you can do is take the chance. or have her tested to be safe.