Please give feedback and criticism on shadow and highlights and whether it does a good job of resembling what it is meant to? Also, how can I add more depth?
Map pin icons/symbols are already a thing and they look like this:
Because they are established and people associate "Map Pin" with this shape you might want to consider following the trend. There is one example of your kind of pin here but its the odd man out.
If you want to keep your pin style you might consider rotating it a bit so it doesn't look like a lollipop.
Don't show the point of the pin if its supposed to be stuck in a map.
Don't make the head too glossy. To add depth add shadows to the parts that are farther away and add light colors to the closer parts.
The grey metal is way too dim for the bright red head.
Look at the one pin in the above example and what they did to add depth: a gradient highlight on the ball and a shadow that recedes away from you. Also a shadow where the pin sticks into the surface. These might be good ideas for yours.