Hi, probably not. Your period was due on the 26th? If your cycles come regularly at about the same number of days from one to the next, you would not have been ovulating on the 23rd. Why not do yourself a favor, though, and get on the Pill or an IUD if you are going to pull stunts like the tip of the penis in the vagina with no protection? Even if you didn't get pregnant this time, you will sooner or later with this kind of approach to sex.