return after RCIA as a sponsor for a newbie
volunteer for RE for children, youth or adults in your new parish, you will probably start out as an aide working with an experienced catechist, at least until your confirmation, but there is no better way to learn than to teach.
next best step after RCIA in my opinion is a bible study, even and especially for someone already well versed in scripture, esp one that examines all of salvation history in light of Catholic teaching. Scott Hahn’s Our Father’s Plan is the gold standard.
I second Puzzleannie’s opinion.
As an RCIA sponsor you will be around people who share your newcomer’s enthusiasm as well as more ‘seasoned’ Catholics who are just as passionate about what they believe, but probably less outwardly exuberant.
Helping with RE and bible study will teach you the substance of that which you feel so compelled to share with others. The Mass, the sacraments, the Bible, and private devotions are all means by which God shares Himself with his people.
There are all kinds of professions that support the Church in some way or another. There are clergy, teachers, theologians, administrators, lawyers, janitors, religious, artists, and accountants. Outreach programs associated with the Church require cooks, doctors, nurses, drivers, construction workers, etc.
Most Catholics are just called to support the Church as an office employee, postal carrier, parent, electrician, etc, in the secular world. In today’s
everyone-should-be-involved-in-a-parish-ministry Church I think it’s important to point out how important, if uncelebrated, these ‘missionaries’ to the local community really are.