Fugue in 11 in F major

Ok i'm still trying to get the hang of analyzing Fugues, so bear with me. The piece begins in F with the subject beginning in the left hand for the first three measures. The right hand then picks up the subject also at measure 5. This is the expository section. The subject is stated again in C at measure 17, notice the b naturals. This piece is really busy, so I could be wrong, but I feel like the modulatory section comes around 31. It seems that Bach moved away from the main subject a little and put it on the backburner. It's still there, really obviously a few measures after at 36. Looking at the piece you can tell the terminative section is reached at 62, when the eb's go away. But to me, it sounds like 61, maybe because the eighth note acsension starts on a C major chord, which is the dominant of F.