Hi Enric,
I think that historically estimations have often been completely off (and I made those mistakes myself). Really just a consequence of not working "requirements" properly, not "listening", not "analyzing" before starting hammering out code. I have been guilty of all of these myself at one point in the past.
Then you pretty much have these trends and methodologies pop up and being sold to you and everyone. And there is an insane amount of FUD out there. I personally think that especially agile estimation (and I have seen it in multiple companies) is completely nuts. Why do I say nuts? Because the answer everyone in every sane company simply wants to hear is "how much $$$$?"
As far as "agile experience" goes, there is no such thing. What is there to require in participating in stand-ups and some meetings?
Don't be afraid, look for a job and company that makes you happy, agile or not. And remember, your first job does not have to be your last.