Now, finally, Study includes the first person to open up (5)
I believe the answer is:
widen
'to open up' is the definition.
(I've seen this in another clue)
'now finally study includes the first person' is the wordplay.
'finally' says to take the final letters.
'study' becomes 'den' (term for a study or office).
'includes' indicates putting letters inside.
'the first person' becomes 'I' ('I' is a first-person pronoun).
The last letter of 'now' is 'w'.
'w'+'den'='wden'
'wden' going around 'i' is 'WIDEN'.
(Other definitions for widen that I've seen before include "Edwin (anag)" , "Expand" , "Add" , "Spread" , "Make less narrow" .)