Your peers (or “competition”) are unlikely pre-meds. First of all, you’re unlikely to run into them other than perhaps in intro CS and intro sciences classes. Secondly, pre-meds would themselves avoid classes that are primarily taken by SCS students. Lastly, if pre-meds are your competition, you’d be fine since you’re admitted into SCS which has tougher academic standards than for the pre-meds.
You should be cautiously confident. Use the summer months to brush up on subjects that you think you’re somewhat deficient. Math is the key to success at SCS. Don’t worry about coding yet, because that’s the easy part and also where the skill levels of freshmen are most disperse (some have years of programming experiences and others have none).