The sensible money has got to be on 73NG/319/320. What with EZY and Ryanair purchasing heaps of them and those are the sort of companies you may well expect to land your first job.
You're not old, but age is not on your side either (is it for anybody over 21?!). You may be better placed going for a turbo rating from which your realistic chances of gaining employment compared to a jet job will probably be greater. From there you can build your hours to a few thousand and then be well placed for jet employment by the time you're 45!