Yes, Bouquet of Flowers is a count noun. It is because the noun can be counted, "Bouquet of Flowers" which means it refers to "Bouquet containing Flowers" . Bouquet, the main thing here can be counted and Flowers also do. So imagine that we have many Bouquet of Flowers, can you count it? Yeah. You can. So therefore Bouquet of Flowers can be counted, and is a count noun.
