How to say "it was my unni's birthday, so I was busy" in Korean?

Question

Answer

제 언니의 생일이었어요. 그래서 제가 좀 바빴어요.
And you can also make one sentence.
제 언니의 생일이었어서 제가 좀 바빴어요!

Answer

If you want to speak that sentence more fluently, it's better to say

'언니 생일때문에 좀 바빴어요"

Answer

it may be ~ 이건 제 언니는 생일이 있었어요 그래서 제게 좀 바빴어요.^^

let other answer it correctly.^^/