Welcome to planDisney, Celene! And, may I add, happiest birthday wishes to you!
It sounds like you're getting ready to celebrate with a trip to 'The Happiest Place on Earth' and I'm thrilled for you because that is exactly how I'd choose to celebrate my 25th birthday (again)! And, a stay at Disney's Grand Californian Hotel & Spa? I can't think of anything more magical.
Celene, I think your best course of action is to go ahead and call the hotel directly and speak to a Cast Member who can place a note on your reservation indicating that you are celebrating something special. I recommend you do this 10 days in advance of your check-in date as that is typically when Cast Members can pull up your reservation information in the system for these types of requests. Of course, special requests like room location, room number, or in your case a personal welcome message on the hotel room's smart TVs are not guaranteed, I have found that Cast Members love to make magic happen for Guests like you!
I do have a few other recommendations for a very, merry birthday in Disneyland Resort, Celene! First, I absolutely recommend you pick up a complimentary celebration button at your hotel's front desk or any of the Guest Relations locations throughout the Disneyland Resort theme parks. They are a simple, but fun way to announce your birthday celebration to others, and I would venture a guess that you'll get lots of birthday wishes coming your way! Plus, you never know what kind of pixie-dusted magic they attract!
Since you are already staying at Disney's Grand Californian Hotel & Spa, you might consider an in-room celebration package through Disney Floral & Gifts. You can find out more details and see an inventory of the available in-room celebrations on their website. Other ideas for a special gift for your 25th year could include a piece of personalized crystal from Crystal Arts on Main Street, U.S.A. or Cristal d'Orleans in New Orleans Square. I just picked up a sweet Cinderella glass slipper for my daughter's upcoming birthday! I also love choosing a new picture frame to commemorate our family visits to Disneyland Resort and then I place my favorite photo from our trip to remember it all year long, and beyond. Whatever suits your fancy, I hope you're able to treat yourself!
Celene, while you're celebrating your 25th birthday, the Walt Disney Company is celebrating its 100th! The Disney100 Celebration continues throughout the rest of this year, and I hope you can enjoy the special offerings during your visit. There's so much to honor about this year, including YOU! If we can help with any other suggestions or recommendations for your upcoming visit, please don't hesitate to reach out to us again. Until then, I'm wishing you an absolutely enchanting birthday celebration from all of us at planDisney!
Blue Skies and Sunshine,
Tishra