is that okay,i believe you can only breed your dog only after 18 months,thanks,,

The average age for a bitch to have her first season is 6 months, with the average gap between seasons being 6 months. The acceptable minimum age for some breed clubs (usually smaller breeds) for bitches to be mated is 18 months, and most of the medium-sized to large breeds shouldn't be mated before they're 2 years old - so probably on their 4th season.

Remember that each time your bitch comes in season it's possible for her to be mated and have a litter - it's your responsibility to ensure this doesn't happen by keeping her away from all other dogs for the 21 to 28 days of each season, not even allowing her in your own garden unattended, and certainly not allowing her off-lead when you're out walking her in out-of-the-way places.

it is true that most breeds are mature physically and mentally to handle a whelp and pups after 18 months but if you have a really immature breed i would wait a little longer. some will season every 4 months make sure you write down the dates so you can estimate when she will be coming into season and going out of season

Hi,
"The Book of the Bitch!" the Breeders Bible!! which I would recommend you get before you
start to breed your girl. Recommends you can start at the third heat, or at 2yrs old.
Regards
Denese

But remember that is "average" and varies from breed to breed. It is best to check with your breed club for their code of ethics