I have been considering doing in under-grad in planning or general design and then a graduate degree in archi so if that's something you would recommend, I may consider that more. Staying around edm would be nice at least for undergrad because I've found it nearly impossible to find a job (most likely due to covid). So being able to stay at home or at least not need to pay rent in Toronto or Vancouver would definitely make the financial perspective better.
As a recent grad of the U of A BFA program in 2019, (which is tied to Bdes, the two programs are combined first year, then branch apart, with some crossover. I did a year of Industrial Design for my degree, for example) stay general in your undergrad, explore what's out there, and KEEP YOUR GPA UP BECAUSE GRAD SCHOOLS ARE ON SOME BS ABOUT ALL THAT.
I went into my bfa intending to go into an M.arch afterwards. this was a common route in the past, with many successful architects in Alberta following this plan. in the 5 years i spent in undergrad (see the extra year of ID i mentioned) the number of M.arch schools in Canada accepting people with other degrees (BAs, BFAs, Bdes, etc) versus a purpose-designed Bachelor of Architecture (Dalhousie and U of C offer this, i'm sure there's others as well now too) shrank from 5-6 to 3. This meant anyone wanting to do an M.arch had fewer options, and the competition for places got more difficult. I'll spare you my own sob story about not getting accepted to any of those schools despite all my hard work because y'all don't need that, but just know it is INSANELY competitive to do an M.arch these days, and tbh, there aren't many jobs for full-on architects out there.
I strongly suggest doing office visits, interviews, anything you can to get a sense of the construction, design, development, and planning industries. there are so many different jobs in these areas, and the type and amount of education you need to do them varies a lot. If you're more technical and love how buildings get built, Architecture Technologies (NAIT or SAIT) are great 2-year programs, and they get you into the industry to work and learn. This is what i did and I love it so far, and actually the BFA was really helpful in this work as well.
I'm not as familiar with planning, but I've heard/seen jobs for people with just a bachelor's degree in some planning fields. it's a super diverse area, talk to people in the industry to get a feel for what path to start down. Go to planning events with the city, just to get a vibe from them. do the online/virtual stuff. The Ualberta planning program is new but already well-regarded; and very progressive. take HGP classes no matter what. I kinda wish i had done planning instead of a BFA, for the career advantages.
Your plan to stay in Edmonton for undergrad makes oodles of sense. save your money, explore, do a 5-year undergrad if you can, so you can take those extra uni courses and take advantage of all the knowledge available on campus. a masters is when you specialize, branch out and explore a bit first, then for your last 60 credits (the bit grad schools focus on) KEEP YOUR GPA UP. like, 3.7-and-higher up. dead serious.
sorry for the ramble, you're just embarking on a big change in your life, and tbh high school rarely prepares people adequately for all the possibilities. be ready to explore and find a different path than what you initially expected. To that end, scope things out as best you can beforehand, before diving into a 4-5 year degree.
edit: I hope this doesn't sound bitter towards U of A and the BFA/Bdes route into architecture; just know that that route is now very competitive, and means committing 6-8 years of your life to education you'll get a lot out of it; I grew immensely in the bfa program, and was able to transfer what i learned to other things. It was just a sideways transition. explore what's out there, and be ready for your career path to be anything but a straight line.