As the readers of this blog probably know, there’s a period during between the holidays of Passover and Shavuot called the Omer. The 49-day period is considered a time of reflection and during it we count up the days in ascending order until Shavuot.
One of things about counting these days is that you’re actually not allowed to say “today is the X day” or “tonight we count X day” until you’ve formally counted the day by preceding it with a blessing and by doing so at the prior evening. For example, if I’m counting the 17th day, I can’t verbalize this when it’s actually time to count it. Then after doing so I can say it’s the 17th day etc.
Typically we say, “yesterday we counted X” and that should tell you what to count when it’s time to do so.