I can co-write the book with you. I am 18 (since you're asking for teens/young adults) but I don't have much experience in writing books, although I know how to write properly (no mistakes and a good range of vocabulary) in both English and Portuguese.
I am a trained English language teacher with a command over the language. I also have a good vocabulary base. Since I am a stay at home mom, I can dedicate quality time to the project.