Looking for planets that could sustain life through the SETI

If the universe is 13 billion years old and the earth is 4 billion years old, then planet earth has been here for one third of all time! 

If the level of life, and intelligent life that has evolved here on earth took this long to get to where we are now, then it seems to me that we should be looking for other planets that, like earth, are 4 billion years old.

These matching ages should suggest a similar evolutionary time line. Other extraterrestrial life forms would likely similarly evolve along this 4 billion year protocol.

The planetary environments of said life forms, however, would likely vary dramatically from ours, as our environment is the result of an extremely complicated series of events, whereby life thrives and adapts through evolution.

It is my belief that the strategy of searching for the same age planets should replace our current criteria of the search for that of water and oxygen on other planets.

SETI stands for the search for extraterrestrial intelligence.