May I use my W-2 income as the basis for contribution to a Roth IRA if that income is from a "special pension" which is part of my early retirement package. I am 79,

I want to open a Roth IRA using my W-2 income even though I am retired.  This income is a "special pension" as part of my early retirement package. Payroll tax  (social security and medicare) is deducted from this income. I am 79 and doing annual RMD from my conventional IRA. 

Is it true that I may withdraw my contributions from a Roth anytime but must wait 5 years to withdraw earnings?