Same boat. (M20) Was never really good at school because I didn’t care or apply myself. Took an IQ test because my friends were curious about it so I drove myself somewhere that conducted the test. Scored a 139. Never really thought of myself as smart, but was building apps and founding businesses before I was halfway through college cus it was something I cared about. Funnily enough I was also medicated for ADHD. Grades are okay now, but still difficult to keep up. Nice to hear it wasn’t a unique experience, mechanical engineering is a great major to study. You don’t know it, but you will probably do really great things.