It is an early 90's steel rigid MTB.
That model of BIOPACE chainring dates it to 1989-1993, as does the Shimano Exage groupset was released first in 1988/9 with a last year of 1993. These parts can be replaced, but given the bike's lack of wear they're probably original
The plastic spoke protector isn't broken so it has not had a hard life.
The only oddities are the aluminium(?) fitment under the downtube (kinda like a bottle cage but not and the rear brake location, down on the chainstay is unusual.
Nice bike! You should enjoy riding it... but first check the tyres - I see lots of cracking on the sidewalls. They may be OK for now. Also check the brake pads, cos they can harden and not brake you effectively.
I'd totally ride your bike (no hidden message there, it looks sweet.)
Sheldon Brown says "An Italian company that moved to Mexico. Some of the Italian examples are exquisite" which is quite a compliment.