The shifted non-local trapezoidal rule (SFTR) with a special shift is adopted to construct a finite difference scheme for the time non-local Allen-Cahn equation. Some essential key properties of the weights of SFTR are explored for the first time. Based on these properties, we demonstrate the discrete energy decay property and maximum-principle preservation for the scheme. Numerical investigations show that the scheme can resolve the intrinsic initial singularity of such nonlinear non-local equations on uniform meshes without any correction. Comparison with the classic non-local BDF2 and L2-1 method further validates the superiority of SFTR in solving the problem. Experiments concerning both discrete energy decay and discrete maximum-principle also verify the correctness of the theoretical results.