I'm also in my fifth year of undergrad, not by choice, though. I couldn't graduate last year even if I wanted to because I switched programs when I was in second year and had a poopy term a couple of years ago.
I really hope they wouldn't look at that and be like "Oh look she's changing majors, she did poorly that semester, she's dumb, etc" and disregard me. I've been doing so much better, especially this current term (like B+ to A- range).
If i don't get accepted to anything this year (BEd or CSE or MT) then I will apply to all of those again next year for sure. However, I'm not sure if my chances next year would be any better, as I hear they are cutting down admission even more and expecting more from us. Not sure if this applies to MT and CSE, or just the BEd's.
EDIT: if I was to get into a BEd this year, I'd have to decide if I want to go with that, OR decline the offers and try again for CSE/MT next year. then again, I don't know how far off I am from being accepted this year, yknow? like if my marks, for example, are completely out of the range, or my statement wasn't sophisticated enough, etc.