"you are old"
A direct translation would be 너도 나이가 들었어 (You've aged too; You've gained years too).
To make it sound more playful, you might say these instead.
- 너도 나이는 못 속여 = You can't hide your age; Your age shows.
- 너도 영원히 젊지는 않구나 = I see that you too are not forever young.
- 이제 너도 아저씨/아줌마 티가 난다 = You're starting to look like a middle aged man/woman too.