Hi @jlrobinson1220gmail-com Joan,
The best way to work out what size a finished garment will be us to draw the stitching line on your pattern piece.
The crown circumference measurement will be taken at the opposite end to where you’ve marked.
Draw a line 1/2″ in from that longer curved edge. Stop the line 1/2″ from each end
The length of that line, doubled, will be the head size circumference of the finished hat.
I guess most heads slope in a predictable way so the circumference where the crown meets the lid is not usually given.
The pattern does run true to measurement, but many of us have found that it’s not true to age/size. Or possibly we have kids with big heads!
I always sized up with this pattern, or used a smaller seam allowance.
Good luck. Once you get the sizing right, it’s a great hat to make over and over again.