Pregnant?

So my husband and I are trying for my baby number #2 but his first baby! I’ve been tracking my period and actually gave it a go on all of my “fertile” days according to this app! My next period is supposed to be by the 15th of December. I’d LOVE to surprise him with a Christmas present announcement but I don’t know if it’s stupid to plan something that may or may not be true since it’s early! How likely would y’all say it is that I could be expecting??