Breeding was AI with fresh semen (not natural).
Originally I planned to breed her during summer, but our summer is going to be way too busy to take care of pups, so we decided to go ahead with the winter breeding instead. A year and a half is considered to be MOST optimal age for first breeding of females. Many reputable breeders feel that way and that breeding first time later may increase the need for C-section. I understand that there is a lot of opinions about the topic, so I would encourage to not make such black and white comments about it.
No, tri markings pose no health risks.