Newbe tri-ing to build endurance

Hi there, I am new to the whole tri thing. I've been riding my bike back and forth to work and my times are coming down. The furthest I've run has been 1.5 miles and I haven't been in the pool in years. But all this is something I want to do so badly. I will be going to a fire fighter academy here in about 2.5 weeks and want to be in the best possible shape for it. Not so worried about the academy as I want to be in better shape. I'm 38, 5'8" and 210lbs. Just thought I's say Hi and tell someone my intentions, it makes me feel a little more comitted.