Good for you being only 14 and doing your research before you buy a dog.
Your mom is absolutely right; avoid the sellers who tell you they are in other countries- they are a complete scam and you will never see your money again!
If you haven't read this already, this link will help you get some ideas of what you and your mother should be asking and looking for in breeders.
http://www.yorkietalk.com/forums/yor...uy-yorkie.html
In general, avoid a breeder who is advertising in the newspaper or strictly on websites. Do you have a vet picked out already? They may be a good resource in finding a reputable breeder in your area.
You might also want to consider looking in to getting a pup from a rescue group and saving a life.
Also, I am going to say this and I hope you aren't offended by it, but a reputable breeder might answer your questions, but should not be making sales arrangements with someone your age. They will need to talk with your mom, too. A person under the age of 18 can not enter in to contracts legally.