Don't worry at 28, you not even close to be being to old. The question arises and should be considered more seriously when you approach late 30's or early 40's , if it it's a gamble worth taking.
Lets be clear, if you have the money to do your training at this age, you have most likely been pretty successful in your "other" career in some way, and you are accustomed to a certain lifestyle.
That is probably the biggest shock to the system, is that the aviation industry treat people not always in the best way and the way you expect to be normal. So your life standards and exceptions should be lowered, at least until you get to a company and position where you feel you are ready to settle.