My dog is only 7 months old and might be pregnant?

I think Nacho might have impregnated her while she was in her heat, which started about 4 weeks ago. What is going to happen if she is pregnant for real? Will it kill her? She's just a baby! She's a papi-pom... Or will the babies just be retarded or something? I DONT KNOW ANYTHING ABOUT THIS SO PLEASE TAKE ME SERIOUSLY! She is the first girl dog I've had so I had to read up on what I do know, and the dogs aren't supposed to be bred until they are three, or have had their third heat? I can't remember. Help???