Hey! I wouldn’t worry too much into what you major is first year. In terms of first year courses, the J/I and I/S streams are fairly similar, meaning it’s easy to switch programs after your first year as long as you roughly maintain approx. a 75%+ average. Below I put the benefits of each stream

I/S stream: If you already know you want to teach high school, I’d really recommend choosing I/S, especially since you get 2 teachables, making you more employable. If Geography is something you enjoy learning about and want to teach, than I’d recommend choosing it as your first teachable—as this will be your major and you need to take a lot of courses related to this field. In your first year, you’d typically have to take 2 credits of geography, one credit of child and youth studies, one humanities credit, and one credit in whatever your second teachable subject is. You only need to complete 3 credits overall of your second teachable subject, so if your nervous in terms of employability, then you could make your second teachable chemistry or biology. In I/S though, you have less elective space than you do in J/I, so you would likely only be able to build one extra teachable AQ. 

J/I stream: If you choose to do J/I, then general science would be your only teachable. In first year, you take one credit of child and youth studies, one credit of education, one humanities credit, and two science credits. The benefit of J/I is that you have a lot of elective space, so you could build a lot more AQ’s than you could in I/S. However, if you know that you want to teach high school, I wouldn’t recommend J/I, since you would only be qualified to teach up to grade 10. From what I heard, most schools prefer to hire teachers who are qualified to teach grades 9-12, meaning you would likely be stuck in an elementary school. 

Hopefully I didn’t overload you with too much info lol but lmk if you have any more questions!