Patrick Swayze was 34 going by the film’s production timeline and 35 at its U.S. release date in 1987. Details:

• Dirty Dancing was filmed during 1986 and early 1987, with principal photography wrapping around spring 1986 to early 1987, depending on source breakdown. Swayze was born on August 18, 1952, which would put him at about 33–34 during filming and 34–35 around the film’s U.S. release in August 1987. The widely cited press and fan sources commonly state he was 34 during the release period, often rounding to 35 in some reckonings. The discrepancy arises from whether one references production dates or release dates. For a precise anchor: his 34th birthday would have been August 18, 1986, placing him at 34 during the 1987 release window.

If you’d like, I can pull exact dates from production schedules and release calendars to pinpoint the age at a specific milestone (start of filming, premiere, or U.S. release).