The O.P is not clear as to how much you are supposed to suddenly know at 18 that you know now.
Assuming that I suddenly knew what I know now at age 18.
1) First, and most importantly, get out of the religion, doing so in a manner that gave the least pain to my family.
2) begin to invest in Property.
3) get a career that would earn me money, to invest in property and Shares.
4) Become Political, and work for a better World.
5) selectively have a number of love affairs.
6) Have children. They have made me a better person.
7) Work to expose Abuse in all its forms, and to change the Law to rectify this.