Translation of puntiagudo

I hope you could understand my last letter to you. You see, when I write in Spanish I am not very confident. I always question myself and each and every sentence takes about fifteen minutes.
My experience at Vocabulix has been great. I really think that this site has helped me a lot in improving my Spanish language skills. I believe that I could learn here several other languages.
After a short guided tour we came back to pick up our luggage and left to the airport. When the airplane took off it was already dark outside. We were surprised about the airline's good condition and service.