The age debate is changing, as traditionally mid-20s was often the cut-off. The job has changed and it is more of a management role than traditionally was the case, but needless to say the ability to fly well is still critical!
Different airlines have different views; RYR prefer youngsters as they're easier to bully, but the real point is that there's been next to no proper recruitment over the last few years, i.e. flybe haven't taken on any non-tagged cadets etc. so it's difficult to say.
A key consideration is whether you can afford to live on e.g. Flybe FO salary, as this is what stuffs up many esp if they've got a loan to service/mortgage /kids etc.
Also remember that on this forum you may hear of a 35 yr old who went straight into a 320 job, but others that have never worked - age is just one factor, but it's increasingly about the individual. Also remember that the industry has fundamentally changed so what was the case 10 years ago, may not be now but nowhere knows yet as proper pair recruitment is still very sparse.
Lastly. the training providers will tell you all sorts depending on how busy they are!