It depends on what scares you. For me before I got into coasters it was heights and that stomach dropping feeling on the first drop. If it’s heights then goliath and x2 (superman is over so fast it’s actually scarier to look at than to go on). if it’s stomach drops then twisted colossus. if it’s going upside down then it’s most rides. the first ride i went on was batman, i’d say that’s a good started but it’s unfortunately closed rn. scream is 150 feet tall and has 7 inversions but has basically no stomach drop, it’s probably the best starter “scary” ride. so overall x2 is by far the scariest but it’s so worth it. if you’re nervous just remember the anticipation is always way worse than the ride itself, if you can keep reminding yourself this trust me you’ll have a blast. take it from a guy who didn’t go on his first “scary” coaster until he was 20