I am trying to enter the date I acquired one of my stocks but it just keeps asking me to do it. I am not sure if I am not doing it correctly or what

You may need to delete the input on that stock and try re-entering it if you are getting the same error repeatedly.  

You will delete the information in the federal interview section. 

1. Select Income & Expenses 
2. Scroll down through all income until you see Investment income 
3. Select Stocks, Mutual Funds, Bonds, Other 
4. If you have any entries, you will see them on the following page titled Your investment sales summary.  Select the trash can to the right to delete the input.
5. You can then re-enter the stock sale by selecting Add more sales
6. Be sure to answer the questions on each screen carefully to ensure all input fields are completed as required