We only know one example of what you'd probably call advanced life forms (and that's us).
It's therefore very difficult to estimate what the average lifespan of an advanced civilisation is.
That's important because it's the last term in the Drake equation
http://en.wikipedia.org/wiki/Drake_equation
That equation seeks to estimate how many detectable (in other words advanced) civilisations there are in the Universe/Galaxy/local area.
Now if the estimates you come up with gives you a high value for that there are lots of advanced civilisations and it's therefore unlikely that we are the most advanced.
If however you get a low value then we might very well be the most advanced.
I would think it's unlikely that we are the most advanced if you're looking at the entire Universe because there are an awful lot of stars out there! Life started very quickly on Earth so it's probably quite common.
But the Sun is not all that old so there's probably a lot of planets that have a bit of a head start on us