Isn''t it funny how everyone has different symptoms normal forf themselves!
I have had 5 pregnancys and 4 babys- my theroy works on length of weeks of sickness , worked the same to the week for my sisters 3 kids too, (she had 1 girl and then two boys,identical weeks of sickness as me!) so I think it's family related.
Age 25 , Preg 1 - 20 weeks bad sickness - had a boy
Age 27 , Preg 2 - 20 weeks bad sickness - I had a boy
Age 28, Preg 3 - 15 weeks bad sickness - I had a girl
Age 37, Preg 4 - 11+ week naseau only - MMC (thought why naseau only)
Age 37, Preg 5 - 20 weeks naseau only -I had a boy (thats how I knew before gender scan!)
So for me the age thing improved my sickness , but still spot on the week for the sickness stopping
Fingers crossed for you cosmic that yours is a girl and only a singleton, the thought of twins with so many kids already would worry me, have an early scan, forewarned is forearmed after all, and it would be lovely to see baby anyway X