Millie Bobby Brown was only 11 years old when most of her fans met her in the first season of Stranger Things –– but the actress is not so little anymore as she just celebrated her 21st birthday.

Millie Bobby Brown turning 20 last year was already mind-blowing and a dose of reality that every child actor has to grow up sometime. Now that the Eleven actress is 21 years old, she made sure to share on Instagram how she celebrated by “smoking” a candle and rocking her mermaid look:

Millie Bobby Brown celebrated her 21st birthday on Wednesday, Feb. 19, and shared a glimpse into how she spent the day, sharing a video of herself sporting platinum blonde fishtail braids and a green bustier as she blew out a candle on a heart-shaped cake.