I *think* the earliest you can test is 6 months, this is what BioTracking says:
Kids less than 6 - 9 months old may test positive for CAE if they have received heat-treated colostrum containing CAE antibodies. We suggest retesting these kids after nine months of age to determine their true...
You should request:
1. what breed you want to breed with
2. make sure the herd is healthy and check for any lumps/sores
3. Make sure your goat and the other is tested for CAE and CL, it will save you a lot of time and heartache in the long run
4. make sure the goat is exactly what you want
5...