Taking my social security

Terry,
I am 66 and turning 67 in November. I had planned to hold off to 70. Now I am afraid after listening to you today on WGN, that waiting the extra 3 years and the SS running out of money or getting less. Should I just pull it and put that in the S&P. I am going to continue to work for at least 2 more years. I do not need the income, actually it will push me into an IRMMA. I am afraid SS will be not there at the amount I am expected to get. If I wait is is 950 more than pulling it 67. Just afraid I will wait and still not get the increase