Does my prayer become invalid if the imam bows before I am able to recite a short surah after Al-Fatiha due to khushu' (devotional humility)?

The prayer is not invalidated by the aforementioned action, but the worshipper should follow the Imam when he bows and not be preoccupied with reciting the surah. One should recite Al-Fatiha with deliberation and care, and if the Imam bows before the worshipper completes Al-Fatiha, then the worshipper must follow him in bowing, according to the majority of scholars (other than the Shafi'is).