I agree with my colleague. If you ever wish to apply for permanent residence in the US this misdemeanor could negatively impact your application. It is best to hire a good criminal attorney who will fight this charge.
Assuming that you are a US citizen, after marriage you could file a green card application for her. It is best to hire an immigration attorney to assist you with this process as it will help you to avoid delays.
it is best to consult with an immigration attorney. As my colleague pointed out there is an intent issue. On a visitor's visa you are only allowed to have the intent to return to your home country. Applying for residency does negate that intent.