I am 22 next month, born in 1989. Given that I live in the UK, I am expected to live another 55 years. I am 30% dead already.
Will I (with your best educated guess) be immortal, or will I die, like the billions that have died before me?
You do realize that by the time you reach the ripe age of 100 years its estimated average life expectancy will be 100 years old (or, making a more conservative estimate, probably around or just over 90 years old). And thats without any groundbreaking stuff happening, just the same paradigm we are stuck in right now, with a more developed version our medicine's current toolset.
I think its very feasible that just on account of regenerative medicine becoming mainstream people will routinely be reaching 90 years old.
And as far as life extension, anti aging, and effective treatments for todays age associated causes of death (ie: cancer, adverse cardiovascular events, diabetes and its associated health problems, etc), its not insane to estimate that in 50 years time SOME progress will be made, so that perhaps people start routinely breaking the 125 +/- 5 years limit with a combination of (in all likelihood aggresive and invasive) therapies.
We are expected to achieve (using old and clunky 20th century as a point of comparison) 400 years of scientific progress in this 21st century. And, since it truly is an exponential curve we find ourselves in as far as this goes, most of that progress will happen towards the next turn of the century.
I think its not crazy to expect to see fountain of youth therapies in the second half of this century. Hell, we are lucky enough to be built modullary (cells, tissues, organs, sistems) and for stem cells to be a key part of cellular turnover. I dont want to drift off on a tangent here, but as complicated as metabolism is, we probably have the basics figured out as far as what goes on at the top and at the bottom of the cascade effects that aging implies.
Aubreys seven causes of senescence is a nice framework to think about the extent of what we need to treat/fix.
And as far as your question goes, it comes down to a series of factors. Your genetic baggage and your lifestyle play a key role. You live in the UK, i would say that helps (as opposed to, lets say, living in Haiti). Also, probably your life expectancy will be directly proportional to the size of your wallet (hell, isnt it already?).
Also, dont forget about cryonics as a last resort.
Financing life extension research and looking both ways before crossing the street give you an extra 2.5% probablity of making it, according to my calculations :-)