Friend of mine had a job on an A320 in Europe, quit, went to 5(!) assessments/interviews before he got hired again at the 6th.
So not making it through one assessment is really just one step on your journey.
Learn from every one and do not be discouraged.
i understood from people who work already that in Europe 260h are enough
There is no such thing as having enough time.
Yes, some lucky souls get picked up by the airlines with 250hrs or less.
The rest of us need to work,work,work and then work some more.
Summer is coming up in Europe, start looking for banner towing and glider towing and sight seeing jobs.
Apply as a Flight attendant over the summer then apply for a Pilot position at the same airline with a Letter of Recommendation from the Head of Cabin Services.
With a bit of luck you've already flown with the Chief Pilot several times and you've left a good impression.
More then one pilot I know got his first jet job that way.
Just as a bit of useless info, it took me 8000 hrs piston to get on a jet.
That and....18 years......and moving to a different continent....and making it through two major downturns in the economy and in aviation.
This is a very tough industry to break into and some final words of wisdom that I've stolen from somebody else:
"There will never be a shortage of inexperienced FO's"
Again:
Learn from every opportunity and do not get discouraged.