Can my aunt get deported for going to the Los Angeles Passport agency?

I'm planning a trip with my cousin to go to Tijuana Mexico in June. I don't think the passport will arrive through the mail on time. I'm 18 and my cousin 17 but my aunt is an illegal alien. I'm scared that if I take them there they might think my aunt is an illegal and deport her or something. When I went to the agency they gave me the passport the same day. If you Travel on Greyhound can my cousin be with me if I'm 18.