But co-signing on a mortgage for you is not normally in her best interest. She takes on 30 years worth of obligation for a debt that she does not get the benefit of enjoying. 30 years is a long time,and should you at any time default on that loan, it would reflect negatively on her. In fact, she would be expected to pay it back should you not be able to pay. Should she EVER want to get a home of her own, she would be showing 100% obligation on your mortgage and have difficulty getting one for her own.
You might want to consider whether there is another alternative, or discussing the full implications of her co-signing so that it's clearly understood.
Best of Luck!
If you owe a lot of bills, you generally don't enjoy disposable income. Without disposable income, any minor financial blip that pops up -- and when owning a home, there are lots of unexpected expenses that can happen -- can wreak havoc on your finances. The lender wants to make sure it's not a huge hassle for you to pay them each and every month of your home ownership.
Not to mention, you don't need the headache of worrying how you're going to make your mortgage payment when you need to pay for other things besides a roof over your head. You might want to consider buying a less expensive home while you continue to pay down your debt and / or work on finding a new job that pays more (but we all know how that goes these days).