Mostly true! The prevailing theory is that “the Big Bang” that formed the known universe created hydrogen, helium, and lithium. Hydrogen and helium are very light and “simple” atoms. Through a bunch of events we got big old burning stars, most of which fuse helium to create more hydrogen. As the star consumes helium and hydrogen it starts to create heavier atoms- with iron being about the heaviest a star is generally theorized to produce because anything heavier takes a lot and would destabilize the whole reaction where the entire process is a result of the natural tendency to try and induce stability. So MOST of the matter in your body can be said to have come from a star or at some point likely came from a star, though a lot of it was processed through other systems before it got to you. If a star goes nova and explodes it can create matter even heavier than iron and throw it out through space to be acted on by forces and systems that may use or transform it.
Of course- iron isn’t ONLY able to form in stars- in theory. It’s a product of atomic change. Atoms can take on subatomic particles or lose them such as shedding electrons etc. In theory iron could be produced by any fusion reaction that met the criteria as well as through other means. Iron is often touted as the “most stable element.” A theory we can’t necessarily prove it that through atomic decay, most atoms heavier than iron would eventually decay to iron and given enough time most lighter atoms would become iron. Of course- the theoretical amount of time required for heavier atoms to decay to iron are timescales many times the estimated age of the universe by some magnitude. So unlikely but possibly. That said-
Since fusion reactions don’t necessarily have to be naturally reduced or sustaining, iron could exist in the universe and even in earth which was created through means other than a star. You could have the remnants of an ancient alien space craft reactor in you for example. Particle colliders could theoretically produce iron under the right circumstances and so you could also have the evidence of some ancient advanced science project in you.
These things aren’t really provable- they’re possibilities that we can rule out and I don’t mention them to rain on a home parade but for the fact that it’s all a bit neat. Realistically though at least some part of you at some point has likely been forged in a star. What can be extra cool is that the theory holds older stars would generally producer relatively lighter atoms and then seed newer stars with heavier fuels for forging which would allow them to create yet heavier atoms. So some atoms in you may have been through several stars!
These things aren’t really provable- they’re possibilities that we can rule out and I don’t mention them to rain on a home parade but for the fact that it’s all a bit neat. Realistically though at least some part of you at some point has likely been forged in a star. What can be extra cool is that the theory holds older stars would generally producer relatively lighter atoms and then seed newer stars with heavier fuels for forging which would allow them to create yet heavier atoms. So some atoms in you may have been through several stars!