If I start PrEP, does this mean I have to take it for the rest of my life?

No. With proper medical guidance, people can safely start and stop taking PrEP at different points in their lives. However, any time you start PrEP, it is important to remember that it generally takes at least 7-22 days of daily use for it to reach full effectiveness. Be sure to consult a knowledgeable healthcare provider before starting or ending a PrEP regimen.

https://www.hrc.org/resources/is-prep-right-for-me