It seemed like she drank the alcohol because Kenny gave her a suspicious look. It seems like she still doesn't want people to know that she is pregnant.
It's kind of interesting how Christa supposedly still wanted to keep the fact that she was "walking for two" a secret. Does she still not completely trust the group? Or is it something she just doesn't want to worry others with. Perhaps she just doesn't want to be treated differently.
Also trust me, that much alcohol wont have much of an adverse effect on the pregnancy, if any at all.
"Don't call me small."