Try finding an accent/EAL tutor or just get a native speaker with some teaching experience to listen to your speech and point out which words you mispronounce -- eventually, you'll pick it all up. Nothing is impossible -- if you set a goal to get a Canadian/North American accent and work towards it, even in small increments every day, you'll get there :)
I spent all of my high school years trying to get rid of my slight Slavic accent (which is hard without being in a 100% English-speaking environment and when switching between 5 languages every single day), and before coming here, I was afraid that people will immediately point my accent out to me and make fun of me, so this summer I had classes with an accent tutor on iTalki and completed this course on Coursera. And this website has a lot of awesome accent tutorials. Try also looking into what mistakes speakers of your native language make, this was actually a game-changer for me!
Somehow, at this stage, most people can't even tell I'm not actually Canadian, so it's possible to change your accent even if you didn't grow up speaking English. It's never too late! Hope this helps!