Age makes no difference when trying to land an airline job, experience is what counts. I started flying at 18, went to the States to train and build experience instructing and flying air taxi. I then returned to the UK at 20 with nearly 2000 hours.
Flew turboprops for a year, now flying the ERJ 145, looking at an upgrade to Captain in about 12 months (at the age of 24)!
Good Luck...and go for it!