Work experience is not really an issue for the airlines; they are in the business of employing pilots, not (at least for our purposes) IT people. Maturity, or lack of it, is of course an issue, but it doesn't sound to me like you'd have a problem on that score. Remember, in normal times, airlines like to get their new FOs as young as possible (but after A-levels or degrees!).
However, times aren't normal and you do need to consider the back-up plan. It may well be that if IT is to be your alternative it would be wise to do a year in industry before you attempt full-time flying training, just so that you are that bit more employeble in IT if you should have to go back to it.
As for the modular vs integrated question, if you can afford it I'd personally recommend integrated simply because the continuity and intensity of the training is more likely to produce the desired result. There is, or at least should be, no competetive advantage for potential employers whether you are an integrated or modular graduate, or where you did your training. It's also true to say that, if you can do back-to-back modules, the continuity advantage of integrated is reduced.
Hope this helps!