My DS17 had an interesting experience last year being in two college Discrete Math classes on the same day that taught the same topic (graphs and/or trees; I’m not an expert). One was a class he sat in on when we toured Harvey Mudd. The other was the class he was taking at our local California community college.
He said that the Mudd class was much more proof-based, while the community college class taught how to use them and do whatever computations. He was not lost in the Mudd class and felt the homework problems were quite doable, so his preparation for a topic in the middle of the semester was fine. That community college class transfers to our local UC as the prerequisite for a very proof-based junior level CS class he’s taking now on “Automata and Formal Languages.” (Again, I have no clue about the content, but it looks tough.) He’s doing fine in that class and finds it the most interesting class he’s ever taken. So again the community college class must have been sufficient preparation, even though he thought it was a bit dull at the time.