When does my ORIGINAL MRD period start? My 70th birthday is 1/10/2018, Is my original RMD period from 1/1/2018 to 3/31/2019?

1/1/2018 to 3/31/2019 is correct ... but remember that  if you wait until 2019 to take the 2018 RMD you must also take the 2019 RMD by 12/31/19 so some tax planning is warranted. 

Keep in mind that any distributions from the account during this period are RMD until your RMD for the account is satisfied.  You must satisfy the RMD for the account before rolling over or converting to Roth any other amounts distributed from the account.