It's a difficult one. I chose school then transition (and thus surgery) and haven't looked back. I make a really good wage now in a job I absolutely love. I worked hard, then got T and the surgery so I could enjoy it all. My concern with the other way about was regret. If I waited, I'd be older trying to start my career and always wondering what if. This way there was no 'what if?' Surgery was always going to happen one day, but in this economy where there's more unskilled people than jobs for them, I'm glad I did it the way I did.
It's essentially your choice at the end of the day. What is more important to YOU. For me, in my twenties, I felt career had to take priority, even if it did make my life a little tougher for a few years, but that won't be the same for everyone.