Hey,

First of all let me clear you few things that will tell if it will be beneficial for you or not. If you want to go canada  just after your 12th then you should have:

1. given toefl exam with minimum score 312 or the ielts exam with 6.0 bands
2. 70% or above in 12th result.

So, If you are clear with above two things then you can go for your under graduation in canada easily and if not you can take a year gap and try to fulfill above mentioned criteria.

On the other if you are planning to go for post-graduation then there will time relaxation for you i.e 5 years . Because a lot of universities there accept one year gap after 12th and a 5 year gap after graduation. So it's totally up to weather you want to go now or after graduation.

Hope these points will help!