Here are three short, sweet messages you can use:
Option 1: Happy birthday, Aunty! Thanks for always making me smile — I hope your day is as lovely as you are.
Option 2: Wishing the happiest birthday to my amazing aunty. I’m so lucky to have you!
Option 3: Happy birthday! Sending big hugs and lots of love to the best aunty ever.
Tip: Pick one and add a short personal line (like 'Love, [Your Name]' or a little memory) before you send it to make it extra special.