I am early 30s and have been advised (rightly or wrongly) not to apply to BA if you want any time in the left seat!
This was due to a rigid seniority system and a 'dead mans shoes' policy of promotion - and looking to get worse in the near future.
If someone with a bit of knowledge on the subject (as I have none - only repetition of rumour) would care to enlighten our x-channel friend Stirling 87...