A. Yes, you can establish and contribute to an IRA for the tax year 2017 from January 1, 2017 to April 17, 2018.
If you have a Keogh or Simplified Employee Pension (SEP) IRA you can receive a filing extension for your 2017 contribution, extending your contribution deadline to October 15, 2018. You can establish and contribute to an IRA for the tax year 2018 up until the time you file your 2018 taxes, with a deadline of April 15, 2019.