It looks like Art.50 is going to be invoked next Wed 29 Mar. At that point Brexit is probably inevitable and irrevocable as it all kicks off and the process runs for at least the next two years. All kinds of other unpleasantness are likely to happen as side effects. Particularly around the other nations in the Union.
So it's probably pointless, but I recommend getting involved in the London march on Sat 25 Mar.
In the mean time here's a short history of the UK's involvement in the EU.
EU: We're joining together, we'd like you to be part of it (1950s)
UK: No thanks, we're fine on our own
UK: we'd like to join now (1960s)
UK: Please, we promise to be good members, we'll change our currency & start using the metric system.
EU: Oh, ok then
UK: Now we've joined we don't like some of the rules.......
And then ...