Your proposal would require an amendment to the Constitution of the United States.
Amendment XIII Section 1.
Neither Slavery or involuntary servitude, except as punishment for crime, whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
Would not be involuntary — a person can choose not to participate, and that means no voting, no govvie job, no public assistance, and no running for office later.
Change your mind when you’re 40? Cool. Go plant trees for a couple of years in one of your State forests.