... then my life took a few turns when I began to more seriously consider my Christian faith. ...
I think there is a component of inner intention that is important; i.e. what is going on in your head/heart as you bow? ... IF you care about adhering to to tennants of your faith, you may want to not bow at least to the shomen.
Or perhaps to reconsider the sginificance of the act -- consider this of O Sensei's Doka which speaks of "jujido" -- the Way of the Cross Sign. Interpret it how you will. Me personally, I follow St. Jerome and see semina verbi:
天 地 の
精 魂 凝りて
十 字 道
世 界 和 楽 の
sekai waraku no
The spiritual essence
of heaven and earth
congeals as the cross of our Path.
The peace and happiness of the world
is linked to Heaven's Floating Bridge.
(Tr. John Stephens)