A lurcher isn't a breed of dog; it's more a generic type of dog (read more).
The most common breeds that go into lurchers are greyhounds, collies, whippets and other hounds. Most dogs reach their basic height by 12 months, but they may grow in height a bit and keep changing internally (skeletal and brain changes) until up to about 2 years old. Then they fill in and their behavior slowly changes from puppy to adult over the next year or so.
It partly depends on the mix of breeds that went make up your lurcher, though. Greyhounds and whippets mature relatively younger, collies mature older -- some people say that collies are puppies until 4-5 years old.
The most common breeds that go into lurchers are greyhounds, collies, whippets and other hounds. Most dogs reach their basic height by 12 months, but they may grow in height a bit and keep changing internally (skeletal and brain changes) until up to about 2 years old. Then they fill in and their behavior slowly changes from puppy to adult over the next year or so.
It partly depends on the mix of breeds that went make up your lurcher, though. Greyhounds and whippets mature relatively younger, collies mature older -- some people say that collies are puppies until 4-5 years old.