To explain how I was taught it (I'm USAmerican so IDK if this is all correct):
- Central America describes the region between Guatemala/Belize and Panama. All of them except Belize are predominantly Spanish-speaking, and all are tropical and forested
- Latin America describes Central America, South America, Mexico, and the Caribbean (though it doesn't include Belize or Suriname). All of them speak a Romance Language as their primary language-- in most cases Spanish, but also sometimes Portuguese and French.
Mexico
is Latin American, but it is
not Central American. Linguistically and culturally, it is more similar to Central America than it is to anglophone North America, but environmentally, it has deserts more similar to the US as well as Central America-like jungles. In short, Mexico is North American geographically as well as Latin American culturally.