That's a big roll to make planesense! The training is certainly no picnic & you will be required to demonstrate you're up to scratch or out you go. Can't comment from direct personal experience of training or instructing in the current "academy" but it doesn't rate highly in the opinion of those I know who've achieved ratings in the last few years.
No idea what sort of money you're on but have you done the sums? Not many of us make it to working past 60 - partly because we can retire earlier but also the shift work gets harder to take & you slow down mentally. I'm mid 40s FWIW & have been at it for 20 years.
Statistically speaking the older you are the harder you'll find the training, but that's just the stats & each individual is different. When was the last time you studied intensively for a prolonged period?
With respect to being treated as a number, it's a serious business with (many) lives at risk so sometimes hard decisions are required & trainees terminated. The sacrifices a trainee has made can't enter into that decision. Thankfully it's not a decision I have to make but those controllers who make it are well & truly aware of what their decision means. Can't speak for the management types. "Would I trust you with my family?" is the question some ask.
All that said I enjoy my job & work with a great bunch of people.