As of February of 2015, it is not feasible for humans of any age to go to Mars, and there is not adequate research to definitively say whether a human could successfully get pregnant and deliver a healthy child on Mars. However, it may someday be possible for humans of all ages to live a full life cycle on the red planet.
Because Mars's gravity is different than Earth's, the biological processes involved in conception and fetal develop may operate differently on Mars than they do on Earth. On top of that, radiation levels on Mars are much different than on Earth because it lacks an atmosphere. As of 2015, scientists don't have enough data to know if these kinds of differences would interfere with a healthy adult woman's ability to conceive.