I definitely see some thinning here, it's about 90 or 95% normal, it's very subtle. Everyone does look thin under direct sunlight and with parted hair, women too.
What is your diet, sleep like? Are you vegetarian, do you get enough iron...? How is your thyroid? etc... it may be tricky to pin down.
You may find it stays the same for years and years... just annoyingly slightly too thin on top.
minoxidil should work better with this, as it does with typical female pattern loss. That seems to be what you have. It's actually very common.
Not all hair loss is male pattern baldness or DHT related.