Of course it won't lose data, but you should pay attention to the format. If the data format you input in the text field is not supported in the data field, this will cause that you can't new a record with your original date format of the text field. But at first you'd better make a backup of your file.
Thank you for your post.
The suggestion by "selfcreator" is definitely valid. However, if there is some concern about losing data, then create an additional DATE field, replace the contents so the original information is intact, and compare. Follow these steps:
1. Create a new temporary date field named TEMP.
2. In Browse Mode, show all records, place your cursor in Temp, pull down the Records menu and select "Replace Field Contents..."
3. In the next dialog box, select the bottom option "Replace with calculated result".
4. In the formula area, enter the name of the original text field that contains the date information. Click OK.
5. Click "Replace". This will place all the contents from the text field into TEMP. If you accidentally entered an invalid date, then the date will not display correctly. Now, you can go into Table view and display just the text field and TEMP and compare. When you see a difference, you can correct accordingly in both fields.
6. When finished, you can either remove the original text field, OR.... if you already have layouts with this text field, change the text field to type Date.
When finished, remove the field you no longer need.
Let me know if you need clarification for any of the above steps.