Adding to intparent’s comments, my D is a CS major (possible math dual major) at Pomona. It is a very popular major right now, and they are actively searching for a new CS professor. So class sizes are not the smallest right now, although I will echo her comments about personal help being easy to obtain (and she went in with ZERO CS experience). There are more CS and math classes available than she can possibly fit in her remaining year there, but she only took one introductory CS class her first year, so your son’s experience would be different.