In 2013, the AGI floor for someone under age 65 is 10% of AGI. The 7.5% floor applies to those 65 or older. Since it is you, and not your mom, who is taking the deduction, you must use the 10%-of-AGI floor.
A fixed deduction allowed to every taxpayer, except those who may be claimed as a dependent by another person. Extra exemption deductions are allowed for a spouse on a joint return and for each qualifying dependent. A deduction of $3,400 is allowed for each exemption claimed on 2007 returns, but the deduction is phased out for certain high income individuals.