No.
We say that it is "choice" but the Many Worlds model also applies to random events such as two asteroids smacking into each other.
It's easier if you look at it like this.
Every time line moves from then to now to the future in what we perceive as linear motion. Setting aside questions of faith, for purposes of this discussion, accept that the Big Bang started all this.
There is a finite amount of energy/matter in the universe and all of it is being used. Once used it's still there (energy can't be destroyed, only reoriented) but it can't be accessed. That's why time travel to the past is, in practical terms, impossible because, once we've used that energy (or those moments) they become unavailable. The future is fog. The present is a burning match. The past is a road made of the ashes. This is the Second Law which says Entropy (or decay or chaos) must increase to maximum.
Bringing in organisms and the ability to make "choices" doesn't really change anything. At any moment I could stand up from the computer and do any number of things. Or I could stay here all night. or the chemicals in my body could stop working in tandem and cause me to explode. All these things and an infinite number of others are always possible. Everything in the universe exists in a partially undetermined state, including all of us. This flux exists at every moment.
By choosing, ANY choice, you are forcing reality into a fixed pattern. which we can call "geoff gets up and walks to the kitchen." But, as long as I do nothing, ALL potential actions are equally likely.
Many Worlds Theory says the universe or, multiverse for us Comics' geeks, is a massive continuum of possibilites, all undetermined and all existing simultaneously.
IF a person could somehow move back into the past (theoretically possible as objects approaching relativistic speeds create a space/time dilation) and somehow make another choice, paradox prevents the erasure of the first line. You can't travel back in time to prevent yourself from building the device that allows you to travel back in time to prevent yourself from building the device that allows you to travel back in time and so on.
What would happen is
1) Something would prevent you from killing Hitler as a boy. Hitler didn't die as a child. So, should you get there, whatever action you take in the past has already occurred and been included.
or
2) rather than erasing your original timeline (not possible because you came from there) you force one of the infinite possible timelines to become actual for you moving forward in the new line with new events spinning off of whatever "change" you made.
The old timeline would simply go on without you from the point where you "went back in time."
And, of course, you would never be able to get "home." All you could do is travel back in time and create another new line.