How to get my mom to co-sign my loan?

Ok, im a college junior and i currently live on campus. but in August i have decided to get an off campus apartment. i don't think i will have enough of financial aid money to pay rent after my tuition and books are payed. And i am trying desperately to find a job so that i can pay for it myself. however, my school said in the event that i don't have enough, i could apply for a loan, and i actually liked that idea. but almost every loan company require a co-signer. I asked my mom to co-sign and she don't want to not because her credit is bad, she has good credit, but she told me that she don't like how it might affect HER in the future in the event if she wanted to do something like get a car loan. she said they probably wouldn't let her buy a car cause she is a co-signer. Can anyone provide me with some insight on the effects of it for her? i know if somehow i am not able to pay, then she would have to pay. but i WILL make sure im able to. but how or what can i say to her to make her feel at ease by being my co-signer?