Horrible GPA first 2 years of undergrad I NEED HELPP WANT TO GO DENTAL SCHOOL!!!

FIRST OF ALL i'm new to the student Doctor Network and I browsed for a while didn't find a similar situation as mine and I apologize if something like this has been posted.

But I am studying Kinesiology at York university and I did horrible in my first 2 years of undergrad in regards to my GPA. I was working full time since my sister couldn't get a OSAP loan for some reasons so I was supporting her with her tuition and to top it off I just wanted to get a degree never thought of anything else after. But now I realised Dentistry is what I want to do after going to International Service Learning in Tanzania Africa for volunteering.

Now I need to know what I should do regards to my C's and D's in my transcript in my first 2 years my academic adviser said I had some options such as:

-RETAKE THE COURSES WITH A GRADES
-OR PETITION ALL MY C's and D'S in my 2 years and if my petition goes through successfully they will completely get rid of the marks from my transcript as if I have never taken them and I must take them again but the downside to that is it will still show in my transcript that I have been enrolled in the University from the year I started my Undergrad so it'll be shown as 6 years if I to retake all the courses.
-Or if the petition is unsuccessful i should just concentrate on my last 2 years of undergrad with to get a high GPA and do a masters in a science field and high mark in DAT + job shadowing hours

Both ways I am kinda behind on credits so I might finish my undergrad in 5 years because I never failed any courses but I have dropped 1 or 2 in the last 2 years so I don't know if finishing your undergrad in 5 years would look bad. I am not applying to dental schools in Canada because it's really hard due to high number of applicants and only few dental schools I am willing to apply to the US dental schools or Australian schools since its now accredited in Canada.

TO BE HONEST THE PASSED 2 YEARS I HAVE STUDIED FOR TESTS AND EXAMS THE DAYS BEFORE AND PULLED A C+ OR B WITHOUT GOING TO LECTURES AND I HAD A 96.4% IN HIGH SCHOOL SO I KNOW I CAN DO THIS BUT NEED TO KNOW WHAT I SHOULD DO?

PLEASE GIVE ME AN ADVISE OR OPINION ON WHAT TO DO I AM STRESSED OUT HERE AND DO NOT HAVE AN IDEA OF WHAT I SHOULD DO FROM HERE !!!!!!!