In general, you should take your RMDs by the end of the year (December 31).
In the year you turn RMD age, you have the option to complete your first RMD by April 1 of next year. If you do this, you'll need to take two distributions in the same tax year:
Complete your first RMD by April 1.
Complete your second RMD by December 31.
This could have tax implications. For more information, consult with your tax advisor.