Hell, you're really not even sure what timeline you're in right now. The future known with perfect certainty would be the present, and the past is mostly speculation and interpretation. Is-ness is the only hard fact. It seems, then, that timelines would be malleable, but since we don't necessarily know what 'hard' time is except as a general trend in entropy, which is not necessarily the 'hard' process we believe it to be (were things indeed more ordered when the universe was a chaotic mass?).
We don't really have a fix on our own timeline. We have few ways of telling which memories are false and which are real, since we seem to construct all of them the moment we go to retrieve them. Our place is a matter of convenience. In that sense, I think yes, you could jump timelines or twist this one into something more closely resembling the timeline you wish. Think of it like this, you want timelines around a certain 'attractor' event, your desired outcome, and you want to get within one of the infinite timelines in which that event or an event very much like it occurs. That's where you would focus your energy, on that moment, that event such as it would be in an ideal scenario. That will should lend some weight to you (you being a series of events) occurring as you are now within such a timeline.