They say the first year doesn’t matter and most of the time it doesn’t, grades wise. But you will hate yourself for not getting into a good study routine or putting the effort in to getting your head around concepts that are built on in the later years. But also, remember that these are probably the last few years where you can do literally whatever you want with few consequences until you retire, so make the most of it. Go places, do things, find out what you like and don’t like, experiment with stuff you don’t know about yet.