I'm 70 di I have to file taxes
No there is not. As long as your income requires filing age does not matter.
There isn't a set age limit, it depends on how much and what type of income you earn during the year. Turbo Tax has a great article to guide you on when you will need to file a return and when you do not need to: https://turbotax.intuit.com/tax-tips/irs-tax-return/does-everyone-need-to-file-an-income-tax-return/L7pluHkoW