I haven't posted here in months and months, but I find myself back here asking the same old question about pregnancy

so my last af was dec 5 lasting (i think I can't remember) about 4 days so it ended on the 9 so that would mean that it should have been here by now but i'm normally a couple days late so no big deal really. So that would mean that I would be ovulating around the week of the 19th. Bf and I aren't ttc, but if it happened I know he would be so excited about it so on the 25th we decided to just do whatever and what ever happens happens. Since it had been 6 days since my most fertile day (going by the 19th) I figured we wouldn't get pregnant anyway since it was so close to the end of my cycle. But like I said here I am wondering if I am.
My son is 8 1/2 months old so it would be alot earlier than I wanted to have another one, but if I am then we'll deal with it. But what I want to know is what you guys think....Do you think it was too late in my cycle for me to get pregnant (starting having unprotected sex on the 25th af was due around the 29th or 30th).