@Sara399 You do not have to either pre-approve or decline an Inquiry- as long as you message back within 24 hours, there are no penalties. You may get prodding messages from Airbnb to pre-approve, but you can safely ignore those. If you clear your cache, those messages should disappear once the Inquiry expires in 24 hours.
If you're interested, I'd also like to invite you to take part in the Spanish speaking community. You'll probably be able to get more responses to your queries over there.