Should I change careers and go to dental school at age 30?

I'm at a crossroads of sorts. My father is a dentist (DDS) and owns his own practice. He is retiring in the next 6 years and has always dreamed of having one of his children take over his practice. Well since I happen to be the youngest of his 3, I would be that child. However, I am already 30 years old! I am also married with a 2 year old and have worked as an advertising executive for the past 8 years. Also, I completed my bachelors degree in 1999! I went to the University of Southern California and graduated with a B.S. in Business Administration (emphasis in marketing). The only science courses I took was Physics and some random Earth science cl. I think my overall GPA was 3.0 or less! Am I just way in over my head? Should I just ask my dad to stop dreaming and live with the reality that he will have to sell his practice to a non family member? By the way, I am all for this if it makes sense and isn't just a pipe dream. Financially, my husband works so we could skate by.