I absolutely loved school and got through with minimum hassle but struggled more in University. You don’t get much attention in big classes sometimes so I would have to make sure to ask questions after.
Yes – lots of subject were hard for me in school. It’s natural not to like ALL your subjects in school. But after a while, you realise even the ones you didn’t particularly like are useful after school.
Have a good basic knowledge of each subject is important (but you don’t need to be a child-genius – I know I wasn’t!)