hotch is 43, आप can see the age in his medical sheet in 5x01. Prentiss 35-36,in 4x17, she hadn't seen her फ्रेंड्स for 20 years, and she was 15 when she lived in Italy, make the maths.
Their full names have never been दिया on the दिखाना (beyond "Aaron Hotchner" and "Emily Prentiss"). The closest gauge of their ages is that Hotch was at the end of his Junior साल of high school in 1987 (so probably 16-17yrs old), meaning he might've been born in 1970/1971. But his timeline is incredibly messed-up (he's been in too many occupations/places in too little time to make sense) so take that with a grain of salt.
Emily was class of '89 at गारफील्ड High according to 'Tabula Rasa', so that might put her at around 1971/1972, assuming she was about 17/18yrsold at time of graduating.