Since my wife has been baptized, is our marriage now sacramental?
The short answer
Yes. A marriage is sacramental when it is valid and both spouses are baptized. Your marriage was presumably valid but not sacramental before her baptism; her baptism did not invalidate it, so at that moment it became a sacrament.
Two requirements
A marriage is sacramental if it is valid and both spouses are baptized. A valid marriage with an unbaptized spouse is not sacramental.
What happened
Before your wife's baptism your marriage was presumably valid but not sacramental. Her baptism did not invalidate it; once you were both baptized, both requirements were met and it became sacramental.
Canon law
Christ raised the marriage covenant to a sacrament between the baptized, so a valid marriage contract between baptized persons is by that very fact a sacrament (CIC 1055).