Perhaps I miss your meaning, but a student doesn’t need to have reached the term where they declare to have ruled out certain majors based on bad initial experiences. For some students (evidently not yours), unsatisfying if not bad experiences are more likely when the classes are large.
I hope you don’t think I claimed otherwise. I do think a student who has spent one-on-one time with a professor discussing academic topics at length is more likely to get helpful guidance from that professor on what research opportunities they might want to consider (not to mention other advice, like electives to consider). It would not be surprising if such a student had some advantage over other students if applying for a research position in that professor’s lab and all else were equal. Sometimes the research idea itself can even come out of those very conversations between professor and undergrad. I also think a student applying to grad school who has had such conversations with a professor, taken their class, and worked in their lab can sometimes expect a deeper letter of recommendation than one from a professor who never had such conversations, didn’t teach the student, and delegated the lab supervision to a grad student.