One of the funny ironies surrounding my Evangelical worries about "Mary worship" is the discovery that my fears were so radically misplaced. Since becoming Catholic in 1987 I have never once met a living soul who worships Mary or thinks her to be a goddess. Meanwhile, one of the first things to present itself to me when I seriously began to look at the Faith was the fact that Catholics do, in fact, adore the Eucharist. They literally worship and adore the Body and Blood of Jesus Christ under the appearance of bread and wine. They accord the Eucharist all the honor due to Almighty God himself, prostrate themselves before it, and offers prayers of praise, worship and petition to it. The Eucharist is, in very truth, God himself according to Catholics. So it's really rather pointless for Evangelicals to focus energy on the phantom Mary worshiper when droves of real live Catholics are falling down in adoration before the Body and Blood. If you are going to attempt a charge of idolatry against Catholics, start there. But before you start, be sure you've disproven that the Eucharist is, in fact, Jesus Christ fully present. If it's not, then yeah: Catholics are idolators. But if it is, then you are the one who sinning gravely by refusing to worship Jesus Christ. The fact that I eventually became Catholic and adore the Eucharist tells you how successful I think you are going to be if you attempt the project of proving worship of the Eucharist to be idolatry.
And something else follows from all this. For if the Eucharist is, as the Church teaches, the "source and summit" of our Faith (in other words, God) then it is supremely the Eucharist to which Mary is referred and to which she refers us. For the Eucharist is Jesus. Mary is, very literally, the Mother of the Eucharist. It's from her that Jesus took the flesh which was transfigured, crucified, raised from the grave, glorified — and which is now offered to us as food and drink.