As you will have no doubt have read on here there are many posts about people 'chasing the dream'. There are horror stories and there are success stories.
What I would say is that don't let either the 'go fo it' or the 'forget it' posts persuade you too much (though thats not to say not to take it on board, the advice on there tends, more often than not, to come from people who know what they're talking about). Ultimately, everyone's situation is a bit different and what's right for one person may be catastrophic for someone else, and vice versa.
My advice would be to get your PPL and simply do some flying initially. This will help you make your decision, because you might find you're happy flying as a hobby or equally, you might find that it cements a decision to pursue a career in aviation. Get involved in the LAA scene as this will be the most cost effective way of keeping current. I'm not a member but I'm told the Solent Strut is well worth a look.
If you want to fly piston engined aeroplanes as a career then I think the key is to enter the market debt free (or with a full-time so you can pay the debt off quickly) because these sorts of jobs wont be the best paid flying jobs (there will be exceptions I'm sure).
There is no easy answer but try and keep your head up.