Do I have to show symptoms to get tested for COVID-19?

Where i live, you need a doctor's order to get tested and its taking around 8-10 days to get test results with the PCR test.  I think some doctor's would recommend getting a test if you had close contact with an infected person for several hours; but some might just recommend self-quarantine for 2 weeks.   If you got infected, it can be anywhere from 1-7 days later before the virus is detectable.  By the time you get the test results, you may be already past the 14-day quarantine. 

Some areas might offer the rapid test, but they are less accurate than PCR and you need to take them multiple times over several days to get reliable results.  So, self-quarantine without testing is usually the most logical course of action unless you get symptoms or unless you can't self-quarantine due to living arrangements or need to go to work. 

Since you were wearing masks and if you were physical distancing as much as possible, you shouldn't have much risk of getting covid 19 from her. 
You should call your doctor and see if you should get tested.

You should get tested. It can take up to two weeks to show symptoms.
I do not what part of the world you are in, so protocols are different. 
If the company did not inform workers, that is shocking, and they should be required by law to inform others.