Armor and helmet for ultra-safe commuting (womens size)?
While you can certainly wear BMX armour, or possibly even use motorbike armour and wear full face helmets,  I would put much more emphasis on changing the way you cycle to reduce the risk from cars. 

You say cars turn without seeing cyclists- well, you have two options:


become more visible. It isn't high fashion, but wear colours and lights, flashing and bright. Use your lane- own it, don't hide over at the side. 
become more aware of other vehicles and make sure you are not where they will be. 


If you wear a full face or motorbike helmet you will not be able to hear as well, so your awareness of other vehicles may suffer. 

Especially on such a short commute cycle, you should be able to take care at each junction.