Luke 2:7 translation and commentary

My translation: And she was giving birth to the son, the firstborn, and she swaddled him and layed him down in a feeding-trough, because there was no room for them at the inn.
All translation is a choice. I could have translated some of the words as "swaddling cloths" and "manger," the problem is I don't really have any experience with swaddling cloths or a manger, in fact the only times we use these words are in reference to the Nativity narratives. I have, however, experience swaddling my two children: also, I know what a feeding trough is, it's what your father-in-law fills with water and reads novels in. Another trick of translation is that the words, especially in Greek, have many meanings, for example: "the first-born" could just as well be "her first-born." Why the choice? In our eucharistic prayers we praise Jesus Christ as the first-born of all creation, the head of the Church, and the author of our salvation. In effect I translated it this way because I have an agenda. I wonder if other translators had agendas too? Nay...