If you did not receive Form 1099-R for the current tax year (2017), then you may delete the information. Each year's tax return should only include the current tax year information unless the amount is related to a carryover amount, etc.

TurboTax will transfer the same sources of income in an effort to make it easier for you to update the amounts for each source. However, you still need to ensure you update all the amounts for 2017 and perform a final review to ensure you have reported all your 2017 income.