regardless of whether or not she gives you her SSN, you paid her enough where she would owe at least self-employment tax. you could tell her that you will have to report her to the IRS so you can file the necessary tax forms for yourself. but first, suggest to her that rather than her SSN she can go to the IRS website an get an EIN immediately. it's up to you as to whether or not you inform her that she may have tax filing requirements.
