Greetings, Moises. I'm glad you brought your question to planDisney!
You're only a few days away from celebrating
Disneyland After Dark: Star Wars Nite with the finest Jedi and Siths in the Galaxy. My whole family loves dressing up for special events at
Disneyland. A few years ago, we donned our galactic finest as
Star Wars characters for Oogie Boogie Bash so I can imagine what fun you are having preparing. Moises, be sure to check out the
Fans of the Force Costume Cavalcade on the night of your event. This march down Main Street, U.S.A. will be a chance to check out the creative costumes of other Guests and show off your own.
Moises, I encourage you to check out the
Dressing for Special Events section on the Disneyland website. It'll provide all the information you need for your costume. Unfortunately, the guidelines for special events state that for Guests 14 years of age and older "Masks of any kind may not be worn, except for medical purposes." So the mask described in your question may not be allowed for the event. You may consider changing your costume or, at the very least, being prepared that your mask may not be permitted through Disneyland Security. Disneyland Cast Members have the final say as to what is permitted but I would hate for you to need a last-minute costume change on the night of the event.
I hope this information helps, and you have a most out-of-this-galaxy time at the event! Be sure to commemorate the event with themed photos and Disney PhotoPass downloads, which are included with your event ticket.
May the Force Be With You,
Melissa