Generally, you should pick these by the difficulties of the fugues. This one has a 4 voice fugue. Since this is your first P&F, I think you should pick a 3 voice one. The number of voices should be marked at the start of each fugue, either by just the number or the phrase "a 3 voci".
I think it is too early for you to start WTC; to manage the fugues you have to operate at least 3 voices fluenlty.You should know that disparity in difficulty between little preludes, inventions and the fugues is huge.I am currently practising French and English Suites of J.S. Bach after having done almost all two-part inventions and still I don't feel prepared to start WTC, even though I'd really like to start it at last.But if you like Bach I recommend you Suites (particular dances also vary significantly in difficulty). They are charming. You will definitely find something for you.Best wishes