[ggeorgovassilis]

> What I'm most afraid of is to be let go after 2-3 months because I'm can't meet their standard which from the interviews I had with them appear to be higher than my workplace.

High performing teams often (though not always) excel at everything, from speed and technology to mentoring and culture which means you might like it there, too. One approach to the situation is to trust that they know what they are doing by hiring you. I think you should discuss your concerns with them. If they still want to go with you, that's a very good sign (or a very bad one, eg. more skilled candidates smelled the trap and dumped them). If they don't, you probably dodged a bullet and can stay at your current job which you love.