そろそろ準備しないと遅れちゃいますよ。

Pronunciation: Sorosoro junbi shinai to okurechau masu yo.

Meaning: We should start getting ready soon or we'll be late.

This phrase uses "そろそろ" (sorosoro) meaning "soon/gradually" and is commonly used to gently prompt someone to begin preparing, showing natural time-awareness in Japanese conversation.