In 1995, 26-year-old Jimmy Smith had 288 receiving yards, enough to finish fourth on the expansion Jacksonville Jaguars. Smith was once a highly-regarded prospect, selected 36th overall in the 1992 draft, but by this point he was on his second NFL team, finishing his fourth NFL season, and those 288 yards were noteworthy because they were the first 288 yards of his professional career.
In 1996, 26-year-old Rod Smith finished 6th on the Denver Broncos with 237 receiving yards. They were not the first 237 receiving yards of his career; after spending 1994 on the practice squad as an undrafted free agent, Smith ranked ninth on the team with 152 receiving yards in 1995, so his career total was now 389.
26 and 27 aren't old for a wide receiver, but they aren't exactly young, either; players by this point are generally no longer considered “prospects” or thought of as still developing.