The Ave Maria consists of three parts:
1. The Angel's salute (Luk. 1, 28)
2. Elizabeth's praise (Luk 1, 42)
3. A short prayer for assistance in extremis.
The first two parts were used in the liturgy since the 11th century, the third part was added in the 15th century.
It is part of the rosary, which is not used in the reformated churches.

Gounod's Ave Maria isn't highly esteemed in the Lutheran church, not because of its text but its musical quality which seems to be more on the saucy side. Who needs Gounod if we have a lot of pure Bach? I wouldn't leave a Lutheran church when hearing it there but be more than astonished.

When singing it you should use the Latin text to which it was originally composed.

Wilfried