ATPL is a seperate license and needed if you want to fly commercial or even some charter. Yes another added cost.
Forget the airlines for the moment, worry about that in 10 years if your thinking Qantas or Virgin. It's not easy out there, need to be very strategic where you fly, relationships you build and what your priorities are. Starting at a similar age (many moons ago), I'd like to think age was on my side. I think some CFIs appreciated some maturity and people with a bit of life experience behind them compared to my opposition which was a half dozen big egoed 20 year olds. Needless to say I got the job.
If I was to do it all again I'd probably learn at the local aero club, build up a reputable profile over time then hopefully get offered a job once the previous instructors move on.