My wife and I are in our early 30s and are here for a 12 month trial. While there doesn't seem to be an abundance of same age peers, there are a few we've ran into. Most of our interests can be handled online, or aren't tightly coupled to age bands so I think we will do well here socially.
For the most part, we have the same pros and cons of living here as the rest of the expats. There are a few things that are either unique to our age band, or in general, a greater factor for us.
Mexico is one of few countries that will provide a long stay visa to people our age without in country work contracts, being a student, etc. Most countries don't have the option, or have a hard set minimum age.
Instead of lower costs making retirement funds go further, lower costs can mean a better work/life balance.
Internet connectivity is limiting for remote work.
I wouldn't be surprised to see groups of younger working expats start to develop down here as internet connections improve.