How much to charge for a project involving only editing the texts of all the product packages for a skincare line?

The company I primary freelance for right now wants to give me another project involving editing all of their products' packages (total of 20 products.) I will only need to edit the texts and nothing about the design. I am still relatively new in the field. I also have a family connection with them, thus making them more willing to provide me work. And in addition, it is still a small brand even though they have been on the Red Carpet and in the Emmy Awards before. Besides within the US, the brand also will be distributed to European countries, China, US, Turkey, and Taiwan. On top of that, I might have to recreate the same packages if the original designer would not give us the original .ai files to work with. They are asking for a flat fee with some flexibility.

With all of the above mentioned, I am wondering what would the standard fee be for this sort of job as a beginner? (From my understanding and google research, I realize that I might have to give both a flat fee and an hourly fee.)

+I still need to figure out if I need to edit also the product labels as well or not.