Is co-signing for a student loan going to affect my credit????

OK, I'm a struggling college student myself... it took about a year for me to even get in college, because I didn't have the funds. Now a family member calls me up and asks if I can co-sign for my cousin whose going to school to be a doctor. The loan amount? A few thousands. She says it will be in default as long as my cousin stays in school, however I also need loans for school, future car, future home, or WHATEVER! Someone please help me out w/this... will co-signing for her, even if she's still in school, mess me up if I want to take out a loan for school as well?? Thanks for your help :).................. By the way, does anyone know of any loans that do NOT require a co-signer? :)