Hi Tamara!
I have not used GDELT, looks pretty cool!
You can certainly use Flink to analyze structured csv files, and people have worked with larger, as well as with smaller datasets using Flink.
So, you can certainly give Flink a spin. Whether Flink is the ideal tool also depends on what kind of analysis you want to run on this data. Posting some more details about your jobs would be helpful.
Kostas