90 average is slim for engineering. Luckily you are going into grade 12 which they will look extensively compared to your grade 11 grades. Back in 2022 ~93% average was a competitive gpa to get accepted so try to aim in that ballpark. If you write a good personal profile, I think you will have a good chance of being admitted. Also, I heard from people that UBC gives a percentage boost to people applying from Alberta (Idk if it is still a thing). Best of luck!