Given the 'retroactive effect' theory of time travel that <PERSON> seems to use (that is, an older self who has time traveled back in time will experience changes occurring to their younger selves concurrently with those changes happening in the time they have reached, and will possess a mixture of memories/effects from their own timeline and ones from the modified timeline). This means that if the person does not travel back, events happen one way. If they do travel back, then any differences in the timeline must be connected to the time-traveler. The time-traveled older self's mere existence starts the butterfly effect you see in many time travel theories (note A Sound of Thunder, or similar works). This form of keeping continuity consistent has problems like any time travel theory, but we'll go with it.
If the older self is collaborating to survive with their younger self, and neither are found out in this, one of two possibilities present themselves:
1. The timeline the older self came from was one where they killed their older self. Like <PERSON>, this old looper prevents their younger self from repeating the performance, and both go free. 494
When the whole thirty years come along, and the young looper goes back, they won't have killed their old self. They could easily die, having lived a different life (which may produce a closed loop of two timelines, figure-eighting into each other), but don't have to (especially if their previous older self did something particular to survive the trip back, and the formerly younger self emulates it when it is their time).
2. The timeline the older self came from was one where they avoided killing their older self. This is a nicer closed loop, as only only one timeline is necessary. Having not killed their older self, and not having been found out, they get sent back, and don't die until they reach old age.
Both of these assume the looper stays in the program after letting their older self go scot free. If they don't, or if the circumstances of going back change each time, each travel back may produce a different timeline, and as each new timeline contains a new travel back, you'll find anywhere from just the one to an infinite number of possible timelines occurring in sequence.
So yes. It could just be a simple "went back, survived, got old", or it could create some crazy loops. 335