You do not need to get an EIN for your coaching business, unless you wish to do so.
If you are going to continue in your coaching business, you may want to consider getting a separate EIN so that you can provide this number to your clients instead of your social security number. You do not need to form a separate legal business entity (such as an LLC or corporation) to obtain an EIN. You are able to apply online via the IRS website at no charge (https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-n...)
You also do not need to consider your assist to be your employee until you have a regular position for them and meet the requirements for them to be considered an employee instead of an independent contractor. For more information on when someone is consdiered an employee, please see https://www.irs.gov/businesses/small-businesses-self-employed/independent-contractor-self-employed-o...
