In the beginning 5.5 to 6 billion years ago a younger slightly smaller star emerged in its dance around the galaxy from a nebula with 2 gas giants around it.
Mercury - the latest piece of rock to be too close to the sun
Venus - at roughly 3.2 billion years old it's slightly younger than earth but growing faster and may have started by earth left overs and fuelled to grow by what jupiter stabalized it's way.
Earth - roughly 4.7 billion years old, a moon probably due to a collision, complex life probably was inherent in the rocks at the start although evolution spawned it's fair share of the seed of life, the earth has grown from a smaller state and is growing now slightly faster than originally, it also has plate tektonics, when it froze over the more complex life moved more to the core leaving only single cell organisms anywhere near the deep freeze, originally the earth may have been closer to the younger star and may have been formed from gravitational stabalizing rock formation of debri collected and effected by the passing of Saturn.
Mars - 5.1 - 2.2 billion years old jupiter has been to close for mars to get to big but it has slowly grown.
Jupiter - 5.5-6 billion years old relatively stable long term orbit.
Saturn was in front of Jupiter but the evolution of the Sun caused Saturn to destabalize and move further away than Jupiter which is where it's rings com from.
Neptune and uranius- 5.2-5.4 billion years old - these planets are because they were in high potential zone for extra solar material to clump.
beyond these planets are the dwarf planets which are to sparse for to much clumping although there could still be a surprise or two out there.
The sun will last for another 2-6 billion years
I know but it's my best guess and it's an original approach to guessing at how the solar system evolved.