Is it a casual thing or do I need a proper shirt?

How to say “Is it a casual thing or do I need a proper shirt?” in Japanese

In Japanese

それってカジュアルな集(あつ)まり？それともちゃんとしたシャツ着(き)ていかなきゃだめ？

Sore tte kajuaru na atsumari? Soretomo chanto shita shatsu kite ikanakya dame?

Is it a casual thing or do I need a proper shirt? in other languages