I understand totally how you feel, OP. In my college classes, not a day goes by that some quick jab at God is said, either by a professor or a student. This is at the University of Florida, just so you know. Some times I would leave class disgusted with myself for not getting the courage to say something, but I’m trying to change and will change. My g/f who is even more new to Catholicism than me has already talked back in class about a professor’s claim that “morals haven’t declined since previous generations, in reality, in opposition to what many think.” Hog wash if you ask me, and a billion other Catholics, or anyone who’s had their eyes open or read about birth control and the 60s sexual revolution.
Stand up next time, if you feel ready. Learning more about our faith will only embolden you more and make you feel more at ease to speak up confidently and knowledgeably, of course with the Holy Spirit within you.