You're of by at least two orders of magnitude - There's one study that claims there's two trillion galaxies.The Hubble Space Telescope (and others) has photographed what scientists consider billions of galaxies. Each galaxy is said to contain over a billion stars. And that is what is visible. To say that only one planet has life given the number of stars in the known universe being a number larger than can be comprehended seems to be very closed minded.
Now defining life as "life as we know it" is also closed minded considering what life has been found right here on our planet that defies logic. (Boy is that statement open to some fun!)
But it's not closed minded to say we're missing a huge part of the the equation and as such, it can't be determined with any level of confidence.
Which is why SETI is a total waste of money so far.
PS that other thread has some good stuff in it; especial from members on sabbatical.