for normal mature hairline, in front it dont looks more V shape. so, its more possible your hairline is not normal mature line.
and there is one positive thing.
your hair density is normal, for many people density reduces as hairline receds.
you two things to do now.
1. healthy lifestyle with maintaining stable hormone levels
2. believing its normal mature hairline and try to stay calm(dont worry, some people here help you believe it)