I answered this in the Family section, but I'll post my answers here too FWIW.
I had a BA in History, worked in human resources for a couple of years, was miserable, so I want back for my M.Ed.
1. It highly depends on your undergrad degree & what subject you're specializing in. I went for secondary social studies & since I had a bachelors in history, the majority of my "subject area" classes I had already taken. It took me 3 years for my masters & that was taking 3 classes a semester. I had to take a class while I was student teaching, which is HIGHLY advised against, but because of scheduling, it's what I had to do to graduate... if I didn't, I was going to have to wait another year. It was a pain in the butt but it was an easy class (Comparative Politics) so it worked out fine.
2. Going back to school wasn't hard at all. I love school & learning. I'd go to college for the rest of my life if I could. It was intimidating to student teach at first, but I got over it quickly enough. Public speaking has never bothered me... when I worked in human resources, I always ran & organized meetings and events, so I'm comfortable in front of people. And honestly, it was probably EASIER for me to be older (well, I was 26) than to be a 21 yo. I taught seniors... so I couldn't imagine only being 3 years older than my students!
3. I don't like corporate America. And as I've mentioned before, I love learning. When I was going to my bachelor's, I was an education major for a year so it had been something I contemplated in the past.
4. IMPOSSIBLE. I graduated in 2007... I don't know a single person that I graduated with that's found a teaching job. I certainly haven't and my license lapsed in '08 so now I have to go back to school again and take more classes to get my license renewed so I can TRY to find a job. And with what our state (and many other states) or doing to the education system and the unions, I can't imagine it's going to get easier to find a job anytime soon. School districts have to pay teachers with master's degrees more money, so they typically hire undergrads first.
5. I was super unhappy working an office job. It just wasn't me. Teaching was my only opportunity to do anything with the field that I love (history). And I wanted a job that would be more compatible with being a mom once I had kids. Plus, my parents paid for my master's degree (it was my undergrad graduation present... I always knew I'd go back for my master's in SOMETHING) so it wasn't going to cost me anything.
6. I honestly wouldn't do it again with the state the public education system is in right now. I'd LOVE to teach.... I thoroughly enjoyed my teaching experience and am dying to have the opportunity to show kids that history can be fun & interesting. And be able to make a difference in kids lives. It was just so... fulfilling, I guess. But right now, it just seems like a waste of money & time to try to get a teaching degree. Especially when you already have gainful employment. I'm hoping by the time I'm done having children & they're both in school that something will have changed and I'll finally get a chance to put my degree to use. Right now it's just an expensive wall decoration.