What Bob Coe said makes a lot of sense. I started out with Nikon, and
stuck with it because my lenses worked with my DSLR. That the Nikon
repair center is located a few minutes from where I live, was also a
factor in my decision.
Don't be mislead by those who will start a Nikon v Canon, war. Just
tune them out. Either Nikon or Canon will make a good choice. If you
really will use you Pentax lenses, go for compatibility. You decision
really depends on your planned use, and the depth of your wallet.

I have to start from zero, my old Pentax lens are either gone or damaged.

D