Can a bull terrier come on heat sooner than 6 months she is 14 months and been on heat once at 10 months?

Yes, a bull terrier can come into heat sooner than 6 months, but it can vary between individuals. Since your dog is already 14 months old and has experienced her first heat at 10 months, she may have regular heat cycles thereafter, typically every 6 to 8 months. However, it's important to monitor her for any signs of heat and consult a veterinarian if you have concerns about her reproductive health.