I am second year premed. If you are passionate about it, do it. If you didn’t start university, you may consider still taking cs major but just completing the prerequisite for the med school. This involves courses such as cell biology, general chem, organic chem and biochem, etc. As long as you finish the required courses and do well in the mcat exam, Med schools Would not care about your major, they may even favour you since you are you are unique candidate, because most premeds major in biology. For me I am doing double majors In biology & psychology with minors in organic chem and pure mathematics. Take your time, make a responsible decision and good luck.
hope this helps.