Good afternoon! With regard to your post:
"In a hearing, in September of 2015, a Judge ruled that I qualify for SSDI, effective March 1st of 2013. ----- Glad to hear that.
"Right now I am 63 years old. I understand that when I reach retirement age my SSDI will switch to SSI. ----- No, SSI is Supplemental Security Income, which is a welfare program administered by the SSA but it is NOT social security. Rather, when you hit your full retirement age (FRA) of 66, your SSDIB will turn into retirement (Social Security Retirement, also known as "old age" benefit) automatically, and remain the full amount it has been in your SSDIB.
"Does my retirement age start at 65, 66 or 70 year old? --- 66.
"And what if I receive less money under SSI then I recieve under SSDI. ------ You won't, unless you have some legal offset, which is unlikely (like outstanding child support, alimony, federal school loan, etc.).
"Does this mean I will get less money to live on per month when Social Security moves me to SSI? ------ No, when it converts you to retirement, it is a name change, generally, with no change to amount, since your Primary Insurance Amount is what it is under both.