Hello @Gaijin_Galaxy!
Ribbon particles can be a bit tricky to work with, because they work differently than other particles. For ribbons, the particle lifetime determines how long the trail stays active (aka how long the trail is). In order to adjust the overall lifetime of a ribbon, you need to set the life cycle of the emitter. In my screenshot, this is probably the setup you want- with the loop duration controlling the ribbon lifetime.
In the case that your ribbons are being generated using a location event from another emitter, setting the particle lifetime in that emitter will determine the lifetime of your ribbons.