There are a multitude of threads on this subject with alot of goods and thoughtful comments from people. Do a search and you'll see how there are many in the same boat as you. Unlike yesteryear age though still a hurdle isn't the insurmountable one it was once. In fact with the market presence of the LCC and the desire to push the retirement age upwards it appears that the more mature ones amongst us are in with a chance. However that certainly doesn't mean it's all plain sailing far from it and you'll still find that you'll need to 'adequately compensate' for your age i.e. extra multi time, turbine time, additional post fATPL courses, etc.
At 30 I don't really think you have too much to worry about BUT consider this. You eventually get going at 31 and qualify at 33 (smiles all round and feeling like a winner) only to find the industry going south because the economy and/or a new conflict in the Middle East. Things don't recover for another 4 years before the first signs of a recovery that makes you 37 maybe more .... Thus it's not necessarily just "how long will it take me to train", there are other extranous factors too that you need to keep an eye on. If you want to do it, research properly when goinf around to visit flight establishments. When listening to the sales pitch try not to become a rabbit dazzled by oncoming traffic that's where reality and dreamland begin to delaminate.
Just a few thoughts hope that helps.