Can being a garuntor on an apartment least disqualify you if you want to get a loan?

My stepmom agreed to be a garuntor on my apartment lease (difference between garuntor and co signer is a garuntor does not go on a lease), she recently backed out though because she is afraid that if she agrees to be a garuntor that when it comes to her getting a loan to fix up her house that the bank will deny her...is this possible? She has great credit and makes good money...