Your question is misleading in two regards:
- The title head of the question, combined with the tag, assumes that there's some age limit to who can receive this virus. There is currently no proven age limit for contracting the zika virus. http://www.cdc.gov/zika/disease-qa.html
It's transmittable through mosquitoes and sex. http://wwwnc.cdc.gov/travel/notices/alert/zika-virus-cape-verde
- "Health authorities and agencies are now investigating the potential connection between microcephaly and Zika virus, in addition to other possible causes. However more investigation and research is needed before we will be able to better understand any possible link." http://www.who.int/features/qa/zika/en/
Unfortunately, according to the CDC, not enough research has been done to address when a developing fetus is safe from microcephaly, as of writing this.
Fortunately, the symptoms are treatable with fluid, rest, and tylenol (to relieve fever and pain).
These are the places currently recorded to have Zika virus.
And here are some facts on prevention to protect yourself in case you live in one of those areas.
I edited your question a bit to clarify and as Carey Gregory already mentioned, microcephaly only occurs in developing children. Since your children are out of the womb, they are no longer at risk of this birth defect.