"Go ye, therefore, into the whole world, baptizing them in the name of the Father and of the Son and of the Holy Spirit."
Good grief....the lengths Roman Catholics go to read into the Scriptures things that are not there.
No where does the verse you've cited say to make this the sign of the Cross.
Really? That’s the kind of thing you worry about, making the sign of the Cross?
Would you have a problem with someone beginning and ending their prayers in the name of the Father, and of the Son, and of the Holy Spirit, without touching their forhead, midsection, and shoulders?