THANKS!

The only thing I really would like to know now is how long you sit reserve? How many years does it take to hold a line?
Depends. Now, isn't that a definitive answer?
At an airline that is growing or at which there is a high rate of attrition so that they are always hiring at the bottom, it doesn't take long to get off reserve.
At a company that has a stable workforce over time, it takes longer because there will be no one below you to push you up and off reserve. Because there are more people coming in and going out there, at EWR it will probably take you less time to clear reserves than it would at IAH.
I had a friend at CO who got IAH right out of training (not the usual rookie assignment) in the Fall of 2000. Because of 9/11 and the fact that CO didn't hire for the next 4 years, he stayed on straight reserve that whole time. However, the last I heard he is finally a line holder.
I have another friend who is a f/a at Frontier. Frontier is growing by leaps and bounds. It took her less than a year to become a lineholder at Frontier because there were so many people hired after her.
The thing you have to get clear in your mind is that you will clear reserves when you clear reserves. (And, you might get off reserve for awhile and get pushed back on because people below you are laid off or quit.) Reserve is part of the job at any airline. And, it takes as long as it takes. You may be on reserve for several years, OR if the company hires a number of new f/as after you, you may be on reserve only a few months.
As someone who took this up as a 5th career, go, do it, and enjoy the ride. It is a fun job. It is not a hard job. It is tiring and you will never get rich, but it is not a hard job.
Also, look at it from the positive side. On reserve, you often get to fly trips that would take you years of seniority to get as a lineholder.