I retired from a non profit organization ( created in 1983 as a political subdivision of the State of Texas) that was exempted from Social Security coverage prior to 1984, thus contributed to a qualified governmental pension plan. I also receive social security benefits from prior employments with 23 YOC.
Will I subject to the WEP or am I exempted?

Hi. Well, it sounds like your non-covered pension might meet one of the exceptions to the Windfall Elimination Provision (WEP), but only if you continued working for the non profit organization when its employees became mandatorily covered by Social Security in 1984. Refer to B.2. of the following section of Social Security's operations manual for more details: https://secure.ssa.gov/apps10/poms.nsf/lnx/0300605362.

Having 23 years of coverage (YOC) as defined in the WEP regulations wouldn't make you exempt from WEP, but it may lessen the impact that WEP if your pension is not exempted from counting for WEP.

Best, Jerry