There are many examples of applicants and/or their parents trying to game the system. IMO, this is not one of them. Obviously a college admissions officer will have an opinion which supersedes either ours, but a kid who spent 11 of his/her 17 years living in Mexico should have no qualms with identifying as Latin@.
Anyway, as I said earlier, the CA splits the questions of race and ethnicity. Specifically:
The questions are optional, so the OP can answer or not answer as s/he sees fit.