I'm married for almost 20 months and filing for a divorce. I would like to know if I can apply for my permanent green card without problems.
Thanks

If you obtained your permanent resident status by marriage to US citizen, divorce before 2 years term will terminate your status unless there are enough evidences to prove that you become victim of domestic violence.

You may be eligible if you can prove that you entered marriage in good faith, and termination of your legal status will cause extreme hardship to you. This is not an easy task, and you need an experienced immigration attorney.