Count the number of Auras you control attached to creatures as the enters-the-battlefield ability resolves to determine how many cards to draw. This will include Sage's Reverie as long as it's still on the battlefield at that time.

An Aura doesn't necessarily need the enchant creature ability for the abilities of Sage's Reverie to count it. For example, an Aura with enchant permanent that's attached to a creature will count.