If you are asking about the live theatre performance, it isn't too late and the show will probably run for a long time. It is currently touring around the UK - at the moment it is in Southampton - and the run will last the whole of 2014 and probably beyond. However, it sells out so fast that many people have had to wait as long as 18 months for a ticket, so unless you are prepared to wait a long time or get lucky with a late cancellation,that could be a problem.
However, a number of cinemas are now staging a filmed version of the live performance. Some people even say it is so well filmed that you get a better view than most people would get in the theatre. It's also a lot cheaper, so you could look up your local cinema listings and see if it's on there. Your final option is to rent the earlier Spielberg film, which is also hugely popular.