The marriage source on his profile is clearly not for a man who lived his life in Virginia. Unfortunately, the scarcity of 18th century Virginia named and a common name frequently causes some random person with no experience to link a marriage record from another country just because it has names they expect and around the time they expect.
It’s not clear why anyone would think the linked birth record is for the same man either.
Almost nobody in Virginia was recorded with middle names then. If there’s no document with it, then it shouldn’t be used. And unfortunately, lots of people find a document somewhere, somewhen for a John Smith and assume it’s their guy. Even if one of them was recorded as Jennings, it requires luck and work to prove that document is for the linked man.
He probably wasn’t 7 years older than his wife, but that doesn’t mean that Family Search has it right. In fact, it could be that FamilySearch has even more insidious data because it feeds into confirmation bias.
My own Smith line goes to Virginia in the 1700s. The earliest progenitor I can document is named William Smith, and there were several, seemingly unrelated William Smiths even in the same county. It makes it much harder to use tax lists, one of the best sources for Virginia research, at least in the late 1700s.
My recommendation is to start later than this profile with all the descendants you can be confident in and try to document the heck out of them. (I have big spreadsheets documenting years of all the Smiths in various counties in tax lists, and then I try to use those, other records, and DNA testing to try to organize them.) Then hopefully you’ll get a little clarity on him, although there’s no guarantee.
Here’s a profile I worked on for a John Smith born around 1736, lived in Virginia, who is not in my direct line:
https://www.wikitree.com/wiki/Smith-195639
(My William’s profile is longer and is still a work-in-progress.) The main point is that these Smith profiles just need a lot of evidence and analysis, or there’s simply nothing credible about them. Even with a lot of evidence, there is still a lot of skepticism indicated about information commonly presented about the man.
