Oh, come now; if I suddenly acquired new sex-related complications on the order of being able to get pregnant, and I was also a new species, I'd probably want to avoid that for at least a while. The character doesn't know about what birth control may or may not be available, what STDs may or may not be rampant, what pregnancy and childbirth are like for cows, or what the sexual mores of the society she's in might be! And also has much more on her mind than figuring out how to get laid, let alone with species she's never considered fornicating with - and the pregnancy one would be from sex with a gender she's never been attracted to. "Yep, probably better not have any sex" is a perfectly reasonable reaction.