It's very likely you saw it, if they were born on the 2nd and you saw a SH at 14.3hh on the first on the month they turned three they would reach their full height on the second
If a horse is born late/mid-month I thiiiink they might continue growing past three to that mid-month mark? So that they grow for 8 even weeks. I could be wrong though!
My girlie did it, she gave me a WWW this RO! Super excited to see what she gives Sunny and others next year! Here's the cutie, I shall look past the roan and sabino, if he's a good boy 👀