The mortgage interest doesn't have to be more than the Standard Deduction amounts - just all your Itemized deductions need to be more. That can include property tax, state withholding and state income taxes paid, charity donations and Medical (over 10% of your AGI).
For 2019 the standard deduction amounts are:
Single 12,200 + 1,650 for 65 and over or blind
HOH 18,350 + 1,650 for 65 and over or blind
Joint 24,400+ 1,300 for each 65 and over or blind
Married filing Separate 12,200 + 1,300 for 65 and over or blind
