How far in advance should i apply?

I am a peruvian citizen but also american citizen. I live in Peru with husband and children, I dont work but my husband supports me financially. Should I apply for a tourist L as an American or Peruvian? Are my chances better if I do it as a U.S. Citizen?
Also I am planning to travel in September. Can I apply for the visa in May? How far in advance can I do it?