This is definitely something that you should bring up at the hearing. Since you have been employed for less than 12 months after having previously been involuntarily separated from your employment, it may be ruled that your wages cannot be garnished at this time.
What rights do I have with garnishment?
Your rights include being sent a notice that explains ED's intention to garnish your wages in 30 days, the amount of your debt, and your right to inspect and copy any records relating to the debt. You also have the right to object garnishment and can avoid garnishment by voluntarily repayment.