Upvote:4
You are OK to travel, if you come back in January 2020 since your Green Card will expire in March of 2020 provided you have a valid travel document (passport or refugee travel document).
I assume your intention is to become a US citizen and therefore please note the following from FindLaw: Immigration
..to become a naturalized citizen ... you must have been physically present in the U.S. for at least 30 months out of the previous five years to establish continuous residency